Characteristics of Nocturnal Insect Communities in Semi-Arid Regions: A Case Study at the Habahu National Nature Reserve of Ningxia, China

Abstract

To explore the spatiotemporal niche characteristics and changing regularities of insect communities under lamps in a semi-arid region, this paper analyzed Levins’ niche breadth index and the Pianka niche overlap index of 10 orders and 19 selected common families or superfamilies of insect communities under lamps from April to September 2018 at six vegetation sites in the Habahu National Nature Reserve, a rare desert grassland–wetland reserve in China. The results indicated the following: (1) Different taxa possess varying spatiotemporal, temporal, and spatial niche breadths, suggesting that insects effectively utilized resources in the Habahu Nature Reserve. (2) Among these groups, in terms of the orders aspect, Lepidoptera had the largest temporal niche breadth, the Hemiptera had the largest spatial niche breadth, and Lepidoptera, Coleoptera, and Hemiptera had relatively large spatiotemporal niche breadths, while Odonata had the smallest niche breadth in all three aspects. The orders of Coleoptera and Lepidoptera had the largest spatiotemporal niche overlap value, while Odonata and Diptera had the smallest. (3) In terms of the common families (superfamilies) aspect, Noctuidae had the largest temporal niche breadth and spatiotemporal niche breadth, while Hydrophilidae had the smallest. The spatial niche breadth of Sphingidae was the largest, while Corixidae was the smallest. Noctuidae and Pyraloidea had the largest spatiotemporal niche overlap value among these herbivore groups, Miridae and Chrysopidae, among the herbivore to predatory groups, and Noctuidae and Braconidae, among the herbivore to parasitic groups. This lays a theoretical foundation for developing Chrysopidae and Braconidae as biological control taxa in the Habahu Nature Reserve.

1. Introduction

The niche is an important theoretical basis for studying plant and animal communities and community ecology [1]. It involves issues such as the allocation and utilization of natural resources, competition and coexistence among species, and the position and role of organisms within the environment. At the same time, it is closely related to a deeper understanding of the structure and function of communities, as well as the feedback coordination and dynamic balance of ecosystems [2]. Research on insect niches is often utilized to explore the characteristics of niche relationships between major pests or between pests and their natural enemies, thereby revealing the degree of interspecific competition or evaluating predation efficacy [3,4]. In studies of insect niches at larger spatial scales, analyzing at the species level requires the consideration of too many environmental factors, which is not conducive to research and analysis. In contrast, conducting analyses at the order level can more effectively unveil the characteristics of insect community niches [5,6]. Phototaxis, a significant behavioral tendency evolved in insects, is exploited in the study of nocturnal insects attracted to light [7]. The variety of insects attracted to light is vast, with observations typically encompassing around eight orders and fifty families, among which Lepidoptera and Coleoptera species predominate. Research on these light-attracted insects primarily focuses on the structure and diversity of insect communities, as well as their temporal dynamics, serving the monitoring of pest populations in agriculture and forestry [7,8,9]. Research on the ecological niches of nocturnal insects attracted to light is relatively scarce. Moths, being one of the primary groups of nocturnal and herbivorous insects, have garnered attention from researchers for their spatiotemporal niche characteristics. For instance, Hou et al. investigated the temporal and spatial niche characteristics of moth communities in the Manghe Macaque National Nature Reserve [10], and Men et al. studied the temporal niche characteristics of moths under artificial sea buckthorn forest lights [11]. However, studies on the ecological niche characteristics of the entire community of nocturnal insects attracted to light are rarely reported.

The Ningxia Habahu National Nature Reserve (hereinafter referred to as the Habahu Reserve) is situated on the southern edge of the Mu Us Desert and is classified as a desert grassland–wetland ecosystem-type reserve. During the 1970s and 1980s, due to a rapid increase in population, overgrazing, and rampant digging for licorice roots, the vegetation suffered severe destruction, leading to extensive land desertification. At one point, three-quarters of the population and arable land in Yanchi County, where the reserve is located, were situated in desertified areas. In recent years, with the support of projects and policies such as the “Three-North” Shelterbelt Program, Natural Forest Resources Protection, Mountain (Desert) Closure for Afforestation, Ecological Compensation, and Forest Tending, the Habahu Reserve has achieved a historic transformation from “desert advancing and humans retreating” to “humans advancing and desert retreating”. The forest coverage rate in the reserve has now reached 40.40%, and wildlife resources have been effectively protected, fostering a positive succession in biodiversity [12].

Elucidating the baseline data on insect diversity at the current stage can indirectly reflect the ecological status of the Habahu Reserve and lay the groundwork for long-term studies on insect community succession and the conservation of insect resources. Building upon the insect surveys conducted by the Lepidoptera Research Group of Nankai University in July 2013 and June and August 2014, the author systematically conducted field investigations on the insect communities in the Habahu Reserve from June to October 2016 and from April to September in 2017 and 2018. Following the identification and organization of specimens, the work “Insects of Habahu” was compiled, documenting 947 species across 665 genera, 144 families, and 12 orders of insects [13]. Based on this work, a preliminary exploration of the spatiotemporal niche characteristics of various ordinal levels within the nocturnal insect community was undertaken, and the niche characteristics of common families (superfamilies) were analyzed. This aims to provide a deeper understanding of the potential competitive, predatory, and parasitic relationships within the nocturnal insect community and to offer foundational data for the development and utilization of natural enemy insects.

2. Materials and Methods

2.1. Study Area

This study was conducted in Habahu Reserve, Yanchi County, Ningxia Hui Autonomous Region, with geographical coordinates between 106.88°–107.63° E and 37.63°–38.03° N, and an elevation ranging from 1300 to 1622 m (Figure 1). It lies in a transitional zone where the Loess Plateau meets the Ordos Plateau, semi-arid regions transition to arid zones, grassland areas shift to desert regions, agricultural lands blend into pastoral areas, and sierozem soils change to brown sierozem soils [14,15]. The reserve is situated in a mid-temperate semi-arid climate zone, characterized by a typical continental monsoon climate with strong winds and frequent sandstorms throughout the year. The predominant wind direction is northwest, with an average annual wind speed of 2.8 m/s. From 1981 to 2010, the average annual temperature was 8.6 °C. Over 80% of the annual precipitation occurs between May and September, with an average annual evaporation of 2249.9 mm, which is 7.97 times the annual precipitation, highlighting the arid and rain-scarce nature of the region. The reserve encompasses various ecosystems, including shrublands, meadows, grasslands, deserts, and wetlands. Floristically, it belongs to the Central Asian subregion of the Eurasian steppe zone, featuring a mix of diverse components that interpenetrate, intermingle, and transition, creating a variety of vegetation types. This diversity provides habitats and abundant nutritional resources for a wide range of insect species [12].

2.2. Insect Collection and Observation

Using a 450 W high-pressure mercury lamp(Minghua Industry and Trade Co., Ltd., Shanghai, China) and a white chemical fiber screen, the phototaxis of insects was utilized to attract and gather them onto the screen [16]. At six selected observation sites (Figure 1; the main plant communities at each site are listed in

Table 1. The vegetation of the sample plots.

Sites	Latitude	Longitude	Elevation	Dominant Species of Plant Community
CN	107.29°	37.64°	1407 m	Diversified Nursery Grounds: Ulmus pumila, Pinus sylvestris, Salix matsudana, Tamarix chinensis
GSW	107.17°	37.96°	1469 m	Shrubland: Artemisia ordosica
HBH	107.04°	37.70°	1452 m	Mixed Woodland and Shrubland: Populus simonii, Hedyarum monglicum
SDC	107.40°	37.92°	1311 m	Mixed Woodland and Shrubland: Populus xiaozhuanica, Ulmus pumila, Salix psammophila, Caragana microphylla, Hedyarum monglicum
EDH	107.29°	37.64°	1407 m	Mixed Woodland and Shrubland: Tamarix chinensis, Ulmus pumila
SQW	107.23°	37.72°	1503 m	Shrubland: Salix psammophila, Hedyarum monglicum

Note: CN, Chengnan; GSW, Gaoshawo; HBH, Habahu; SDC, Sandaochuan; EDH, Erdaohu; SQW, Shaquanwan. The same below.

), observations were conducted monthly, avoiding the two days around the full moon. In the case of rain or strong wind, the observation was postponed. The light trapping started between 19:30 and 20:00 and ended between 23:30 and 24:00, with the peak period of insect activity concentrated between 20:30 and 21:30. The number of individuals from each order, family, or group was recorded. If new species appeared on the screen after the main observation period but before the end of the light trapping, they were counted and recorded, while previously recorded species were not recounted. After the observation, the number of individuals from each order and common families (or superfamilies) was promptly tallied and organized.

First, the niche characteristics of the insect community under the light at the Habahu Reserve were studied at the order level. Second, insects from the same taxonomic group exhibited similar dietary habits, especially for herbivorous insects, which tend to feed on plants that are similar or belong to the same family [17]; the study delved into the family level (or superfamily), selecting 19 common families or superfamilies. By calculating their niche breadth and niche overlap indices, a preliminary exploration of the niche characteristics of insects with different feeding habits under the light at the Habahu Reserve was conducted.

2.3. Niche Measurement Indices

The niche breadth was calculated using Levins’ formula [18]:

$${\mathrm{B}}_{\mathrm{i}}={\displaystyle \frac{1}{\sum _{\mathrm{i}=1}^{\mathrm{s}} P_{\mathrm{i}}^2}}$$

where Bi represents the niche breadth, and Pi denotes the proportion of the species in the ith unit of a resource sequence.

The niche overlap index was calculated using Pianka’s formula [19]:

$${\mathrm{Q}}_{\mathrm{i}\mathrm{j}}={\displaystyle \frac{\sum _{\mathrm{k}=1}^{\mathrm{n}} \left({\mathrm{P}}_{\mathrm{i}\mathrm{k}}{\mathrm{P}}_{\mathrm{j}\mathrm{k}}\right)}{\sqrt{\sum _{\mathrm{k}=1}^{\mathrm{n}} {\mathrm{P}}_{\mathrm{i}\mathrm{k}}^2{\mathrm{P}}_{\mathrm{j}\mathrm{k}}^2}}}$$

Qij represents the niche overlap value between species i and species j; Pik and Pjk denote the proportion of individuals of the ith and jth species utilizing the kth resource unit relative to the total number of individuals of that species in the resource, and n represents the number of resource units.

The two-dimensional spatiotemporal niche index was calculated as the product of the temporal niche index and the spatial niche index [20].

2.4. Data Organization and Analysis

Microsoft Office Excel 2019 (Version 2019; Microsoft Corporation, Redmond, WA, USA) was used to organize the number of individuals from each order or common family (or superfamily) across different months and observation sites. The spaa package in R version 3.6.2 (R Foundation for Statistical Computing, Vienna, Austria) was employed to calculate the temporal, spatial, and spatiotemporal niche indices for each order or common family (or superfamily) [21].

3. Results

3.1. Niche of Insect Communities at the Order Level

3.1.1. The Temporal and Spatial Distribution of Insect Orders in the Habahu Reserve

A total of 10 orders, comprising 20,444 individual insects, were observed under the light in the Habahu Reserve. The primary groups included Lepidoptera, Coleoptera, Diptera, and Hemiptera, which accounted for 88.62% of the total individuals. Among these, Lepidoptera and Coleoptera alone represented 55.27% of the total observed individuals.

The temporal distribution of the number of individuals across different insect orders is presented in

Table 2. Temporal distribution of individual numbers across different orders in the Habahu Nature Reserve.

	Month	April		May		June		July		August		September
Order		Number of Individuals	Percent (%)	Number of Individuals	Percent (%)	Number of Individuals	Percent (%)	Number of Individuals	Percent (%)	Number of Individuals	Percent (%)	Number of Individuals	Percent (%)
Lepidoptera		467	38.76	1186	30.03	1066	40.73	1848	27.08	2015	44.40	699	53.32
Coleoptera		47	3.90	801	20.28	712	27.21	1384	20.28	1003	22.10	72	5.49
Hymenoptera		24	1.99	29	0.73	48	1.83	350	5.13	103	2.27	244	18.61
Diptera		559	46.39	1477	37.40	238	9.09	499	7.31	475	10.47	92	7.02
Neuroptera		4	0.33	209	5.29	128	4.89	715	10.48	241	5.31	106	8.09
Hemiptera		104	8.63	246	6.23	420	16.05	1966	28.81	663	14.61	80	6.10
Trichoptera		0	0.00	0	0.00	4	0.15	6	0.09	10	0.22	9	0.69
Orthoptera		0	0.00	1	0.03	1	0.04	47	0.69	18	0.40	8	0.61
Odonata		0	0.00	0	0.00	0	0.00	1	0.01	3	0.07	0	0.00
Mantodea		0	0.00	0	0.00	0	0.00	8	0.12	7	0.15	1	0.08

. In April, only six orders were observed: Lepidoptera, Coleoptera, Hymenoptera, Diptera, Neuroptera, and Hemiptera. Diptera had the highest number of individuals, followed by Lepidoptera, with these two orders together accounting for 85.15% of the total individuals. In May, the dominant orders were Diptera, Lepidoptera, and Coleoptera, which collectively made up 87.72% of the total individuals. In June and July, the dominant orders were Lepidoptera, Coleoptera, and Hemiptera, with these three orders representing 83.99% and 76.17% of the total individuals, respectively. In July, Neuroptera and Diptera also accounted for 10.48% and 7.31% of the total individuals, respectively. In August, the dominant orders were Lepidoptera and Coleoptera, constituting 66.51% of the total individuals, followed by Hemiptera and Diptera at 14.61% and 10.47%, respectively. In September, the dominant orders were Lepidoptera, Hymenoptera, and Neuroptera, making up 80.02% of the total individuals.

In Lepidoptera, the dominance of light-trap catches across all months is closely related to their nocturnal activity and phototaxis. Coleoptera are the dominant group from May to August, with fewer catches in April and September when nighttime temperatures are lower. The lower number of Diptera caught in June may be related to the dry and rainless climate characteristic of that month. Hemiptera reach their peak in light-trap catches in July, likely because the nymphal stage dominates from April to June, during which their activity is weaker. August is the growing season for plants in the Yanchi County region [22], and by July, many species reach the adult stage. Herbivorous species may disperse or migrate to occupy more ecological niches, resulting in higher light-trap catches. As the number of prey or hosts increases, Neuroptera and Hymenoptera show higher light-trap catches from July to September.

The distribution of insect orders across observation sites is shown in

Table 3. Spatial distribution of individual numbers of insects across different orders in the Habahu Nature Reserve.

	Sites	CN		GSW		HBH		SDC		EDH		SQW
Order		Number of Individuals	Percent (%)	Number of Individuals	Percent (%)	Number of Individuals	Percent (%)	Number of Individuals	Percent (%)	Number of Individuals	Percent (%)	Number of Individuals	Percent (%)
Lepidoptera		1042	34.77	958	29.53	788	29.09	1606	32.59	1733	41.28	1154	48.73
Coleoptera		305	10.18	920	28.36	570	21.04	1184	24.03	751	17.89	289	12.20
Hymenoptera		45	1.50	338	10.42	96	3.54	116	2.35	129	3.07	74	3.13
Diptera		976	32.57	288	8.88	480	17.72	1021	20.72	340	8.10	235	9.92
Neuroptera		150	5.01	189	5.83	103	3.80	355	7.20	477	11.36	129	5.45
Hemiptera		461	15.38	532	16.40	657	24.25	615	12.48	743	17.70	471	19.89
Trichoptera		14	0.47	7	0.22	2	0.07	0	0.00	4	0.10	2	0.08
Orthoptera		3	0.10	10	0.31	11	0.41	28	0.57	12	0.29	11	0.46
Odonata		1	0.03	2	0.06	0	0.00	0	0.00	1	0.02	0	0.00
Mantodea		0	0.00	0	0.00	2	0.07	3	0.06	8	0.19	3	0.13

. At the Chengnan site, Lepidoptera and Diptera were the most abundant orders, accounting for 67.33% of the total individuals, followed by Hemiptera and Coleoptera. At the Gaoshawo site, Lepidoptera, Coleoptera, and Hemiptera were the dominant orders, making up 74.29% of the total individuals. At the Habahu site, Lepidoptera, Hemiptera, Coleoptera, and Diptera were the dominant orders, accounting for 92.10% of the total individuals. At the Sandaoquan site, Lepidoptera, Coleoptera, and Diptera were the dominant orders, representing 77.33% of the total individuals, followed by Hemiptera. At the Erdaohu site, Lepidoptera, Hemiptera, and Coleoptera were the dominant orders, making up 76.87% of the total individuals. At the Shaquanwan site, Lepidoptera was the dominant group, accounting for 48.73% of the total individuals, followed by Hemiptera at 19.89%. Lepidoptera species were abundant at all observation sites as the gradually restored vegetation communities provided rich food resources for Lepidoptera larvae. The number of individuals of Lepidoptera, Coleoptera, Diptera, and Orthoptera at the Sandaoquan site was higher than at other sites, indicating that the complex mixed woodland of trees and shrubs provides more ecological niches for insects.

3.1.2. The Niche Breadth of Insect Orders in the Habahu Nature Reserve

From

Table 4. Niche breadth of order in the Habahu Nature Reserve.

Niche Breadth Value	Lepidoptera	Coleoptera	Hymenoptera	Diptera	Neuroptera	Hemiptera	Trichoptera	Orthoptera	Odonata	Mantodea
Temporal niche	4.9429	3.9614	3.2429	3.6772	3.0726	2.6549	3.6094	2.1643	1.6000	2.2456
Spatial niche	5.5577	4.8744	3.9539	4.4997	4.4836	5.8209	3.1264	4.3980	2.6667	2.9767
Temporal–spatial niche	27.4712	19.3094	12.8221	16.5463	13.7763	15.4539	11.2844	9.5186	4.2667	6.6845

, it is evident that the temporal niche breadth of insects varies among different orders, with Lepidoptera having the highest value (4.9429), followed by Coleoptera (3.9614), Diptera (3.6772), Trichoptera (3.6094), Hymenoptera (3.2429), Neuroptera (3.0726), Hemiptera (2.6549), Mantodea (2.2456), Orthoptera (2.1643), and Odonata (1.6000). This indicates that Lepidoptera insects have a large population size, long activity cycles, and utilize temporal resources most efficiently. In contrast, the lower temporal niche breadth values of Orthoptera and Odonata may be related to their predominantly diurnal activity patterns, resulting in fewer individuals being observed at night.

The spatial niche breadth is relatively high for Hemiptera (5.8209) and Lepidoptera (5.5577), followed by Coleoptera (4.8744), Diptera (4.4997), Neuroptera (3.9539), Orthoptera (4.3980), Hymenoptera (3.9539), Trichoptera (3.1264), Mantodea (2.9767), and Odonata (2.6667) (Table 4). This indicates that Hemiptera, Lepidoptera, and Coleoptera are evenly distributed across different observation sites and utilize spatial resources efficiently. In contrast, Odonata and Mantodea have fewer individuals in various habitats and are unevenly distributed in the Habahu Nature Reserve.

The spatiotemporal niche reflects the distribution of taxa across both time and space dimensions. It is not only an essential component of multidimensional niches but also a specific representation of them [2]. Among the spatiotemporal niche breadths, Lepidoptera (27.4712) has the highest value, followed by Coleoptera (19.3094), while Mantodea (6.6845) and Odonata (4.2667) have the lowest values (Table 4). This demonstrates that Lepidoptera and Coleoptera have long activity cycles and wide spatial distributions, allowing them to utilize niche resources more fully. In contrast, Odonata and Mantodea have shorter activity cycles and narrower spatial distributions, resulting in the less effective utilization of nighttime niche resources.

3.1.3. The Niche Overlap of Insect Orders in the Habahu Nature Reserve

The spatiotemporal niche overlap among insect orders is shown in

Table 5. The spatiotemporal niche overlaps of insect order in the Habahu Nature Reserve.

Order	Lepidoptera	Coleoptera	Hymenoptera	Diptera	Neuroptera	Hemiptera	Trichoptera	Orthoptera	Odonata
Coleoptera	0.8869	—
Hymenoptera	0.5872	0.6448	—
Diptera	0.6331	0.5997	0.2361	—
Neuroptera	0.8302	0.8406	0.6403	0.4553	—
Hemiptera	0.8076	0.8347	0.6852	0.4127	0.8958	—
Trichoptera	0.5300	0.3661	0.4774	0.2562	0.3564	0.4162	—
Orthoptera	0.7090	0.7847	0.6385	0.3193	0.8318	0.8515	0.2404	—
Odonata	0.4726	0.4468	0.4066	0.1714	0.3518	0.3761	0.5940	0.2503	—
Mantodea	0.7008	0.5773	0.3836	0.2032	0.7832	0.7054	0.2152	0.6639	0.3025

, where Hemiptera and Neuroptera exhibit the highest overlap indices. Combinations with an overlap index greater than 0.8 include Coleoptera and Lepidoptera (0.8869), Neuroptera and Lepidoptera (0.8302), Hemiptera and Lepidoptera (0.8076), Coleoptera and Neuroptera (0.8406), Coleoptera and Hemiptera (0.8347), Neuroptera and Orthoptera (0.8318), and Hemiptera and Orthoptera (0.8515). This indicates that these groups share highly similar characteristics in their utilization of spatiotemporal niche resources, suggesting potential trophic-level relationships such as competition, predation, or parasitism among these taxa. The lowest overlap value is observed between Odonata and Diptera, likely because Odonata are mostly active during the day, while Dipteran species are primarily nocturnal, resulting in lower niche overlap.

3.2. Niche Characteristics at Common Families (or Superfamilies) Level

3.2.1. Niche Breadth of Common Insect Families (or Superfamilies) in the Habahu Nature Reserve

Using the aforementioned methods, the distribution of individual counts of common insect families (superfamilies) across time and space was statistically analyzed (see Appendix A 

Table A1. The temporal distribution of common family (or superfamily) individual number in Habahu Nature Reserve.

	Month	April		May		June		July		August		September
Taxa		Number of Individuals	Percent (%)	Number of Individuals	Percent (%)	Number of Individuals	Percent (%)	Number of Individuals	Percent (%)	Number of Individuals	Percent (%)	Number of Individuals	Percent (%)
Sphingidae		6	0.56	28	0.79	15	0.70	22	0.42	0	0.00	4	0.35
Noctuidae		97	9.13	174	4.91	73	3.42	295	5.68	255	7.26	85	7.52
Geometridae		81	7.63	179	5.05	82	3.84	346	6.66	230	6.55	38	3.36
Gelechioidea		75	7.06	248	6.99	331	15.50	485	9.34	589	16.76	208	18.41
Tortricidae		20	1.88	81	2.28	81	3.79	104	2.00	177	5.04	150	13.27
Plutellidae		59	5.56	27	0.76	59	2.76	6	0.12	24	0.68	31	2.74
Pyraloidea		114	10.73	400	11.28	325	15.22	485	9.34	607	17.27	134	11.86
Cicadellidae		0	0.00	55	1.55	239	11.19	1318	25.39	456	12.98	21	1.86
Miridae		104	9.79	93	2.62	51	2.39	509	9.80	154	4.38	55	4.87
Corixidae		0	0.00	100	2.82	30	1.41	78	1.50	10	0.28	4	0.35
Chironomidae		436	41.05	1133	31.95	33	1.55	27	0.52	5	0.14	5	0.44
Hydrophilidae		21	1.98	388	10.94	9	0.42	4	0.08	60	1.71	13	1.15
Scarabaeoidea		14	1.32	170	4.79	177	8.29	224	4.31	49	1.39	12	1.06
Staphylinidae		6	0.56	220	6.20	149	6.98	141	2.72	136	3.87	1	0.09
Anthicidae		0	0.00	3	0.08	212	9.93	145	2.79	52	1.48	0	0.00
Carabidae		1	0.09	10	0.28	103	4.82	274	5.28	437	12.44	24	2.12
Chrysopidae		4	0.38	209	5.89	119	5.57	609	11.73	170	4.84	101	8.94
Ichneumonidae		19	1.79	17	0.48	47	2.20	106	2.04	93	2.65	236	20.88
Braconidae		5	0.47	11	0.31	0	0.00	14	0.27	10	0.28	8	0.71

and

Table A2. The spatial distribution of common family (or superfamily) individual numbers in Habahu Nature Reserve.

	Sites	CN		GSW		HBH		SDC		EDH		SQW
Taxa		Number of Individuals	Percent (%)	Number of Individuals	Percent (%)	Number of Individuals	Percent (%)	Number of Individuals	Percent (%)	Number of Individuals	Percent (%)	Number of Individuals	Percent (%)
Sphingidae		14	0.64	15	0.55	13	0.64	14	0.33	8	0.23	11	0.58
Noctuidae		119	5.47	202	7.35	85	4.17	264	6.27	161	4.60	148	7.76
Geometridae		141	6.48	114	4.15	68	3.34	157	3.73	224	6.40	252	13.21
Gelechioidea		222	10.20	230	8.37	142	6.97	337	8.01	720	20.57	285	14.94
Tortricidae		99	4.55	132	4.80	80	3.93	63	1.50	176	5.03	63	3.30
Plutellidae		64	2.94	11	0.40	67	3.29	12	0.29	48	1.37	4	0.21
Pyraloidea		297	13.65	217	7.89	269	13.21	650	15.45	313	8.94	319	16.72
Cicadellidae		118	5.42	455	16.55	372	18.26	421	10.00	435	12.43	288	15.09
Miridae		296	13.60	56	2.04	141	6.92	127	3.02	185	5.28	161	8.44
Corixidae		16	0.74	0	0.00	115	5.65	59	1.40	32	0.91	0	0.00
Chironomidae		466	21.42	200	7.28	103	5.06	820	19.49	47	1.34	3	0.16
Hydrophilidae		46	2.11	210	7.64	177	8.69	30	0.71	21	0.60	11	0.58
Scarabaeoidea		44	2.02	169	6.15	115	5.65	75	1.78	164	4.68	79	4.14
Staphylinidae		24	1.10	79	2.87	12	0.59	284	6.75	221	6.31	33	1.73
Anthicidae		42	1.93	29	1.05	61	2.99	195	4.63	57	1.63	28	1.47
Carabidae		36	1.65	347	12.62	28	1.37	271	6.44	109	3.11	58	3.04
Chrysopidae		88	4.04	176	6.40	93	4.57	313	7.44	451	12.88	91	4.77
Ichneumonidae		34	1.56	102	3.71	91	4.47	104	2.47	123	3.51	64	3.35
Braconidae		10	0.004	5	0.18	5	0.25	12	0.29	6	0.17	10	0.52

for details). This analysis yielded the temporal, spatial, and spatiotemporal niche breadths of each family (

Table 6. Niche breadth of common family (or superfamily) in the Habahu Nature Reserve.

Diet	Family (Superfamily)	Niche Breadth Value
		Temporal Niche	Spatial Niche	Temporal–Spatial Niche
Herbivorous groups	Sphingidae	3.6408	5.7930	21.0912
	Noctuidae	4.6916	5.3332	25.0212
	Geometridae	4.1659	5.1978	21.6535
	Gelechioidea	4.6729	4.4858	20.9617
	Tortricidae	4.8073	5.1802	24.9028
	Plutellidae	4.5807	3.7991	17.4025
	Pyraloidea	4.7367	5.1383	24.3386
	Cicadellidae	2.1758	5.3959	11.7404
	Miridae	3.0308	4.9926	15.1316
Omnivorous groups	Corixidae	2.8821	2.7401	7.8972
	Chironomidae	1.8204	2.8506	5.1892
	Hydrophilidae	1.5823	3.1013	4.9072
	Scarabaeoidea	3.6883	5.0594	18.6606
	Staphylinidae	3.9115	3.1001	12.1260
	Anthicidae	2.4714	3.5083	8.6704
Predatory groups	Carabidae	2.5991	3.4133	8.8715
	Chrysopidae	3.1398	4.1145	12.9187
Parasitic groups	Ichneumonidae	3.4208	5.3792	18.4012
	Braconidae	4.5534	5.3581	24.3976

) and their spatiotemporal niche overlaps (

Table 7. The spatiotemporal niche overlaps of common family (or superfamily) in the Habahu Nature Reserve.

Family (Superfamily)	Sphingidae	Noctuidae	Geometridae	Gelechioidea	Tortricidae	Plutellidae	Pyraloidea	Cicadellidae	Miridae
Noctuidae	0.7077
Geometridae	0.6826	0.8905
Gelechioidea	0.5239	0.8160	0.8540
Tortricidae	0.5201	0.7624	0.7085	0.8726
Plutellidae	0.4567	0.3501	0.3310	0.4291	0.5214
Pyraloidea	0.6873	0.9272	0.8349	0.8144	0.7186	0.4214
Cicadellidae	0.5669	0.7906	0.7797	0.6948	0.5684	0.1749	0.6805
Miridae	0.6213	0.7102	0.8230	0.6475	0.5582	0.3301	0.6574	0.7289
Corixidae	0.6496	0.4387	0.3833	0.3468	0.3203	0.3262	0.5223	0.4486	0.4272
Chironomidae	0.5584	0.3663	0.2557	0.1682	0.1707	0.2497	0.3945	0.0397	0.1637
Hydrophilidae	0.5657	0.3143	0.2203	0.1741	0.2883	0.2324	0.2863	0.0768	0.1143
Scarabaeoidea	0.8305	0.7139	0.7253	0.7057	0.6359	0.4097	0.6588	0.7523	0.5850
Staphylinidae	0.5987	0.7270	0.6355	0.7306	0.5426	0.2679	0.7945	0.5088	0.3948
Anthicidae	0.4853	0.5272	0.4512	0.5077	0.3549	0.3080	0.6514	0.5638	0.4198
Carabidae	0.3053	0.7661	0.5567	0.6064	0.5957	0.1309	0.6764	0.6670	0.3617
Chrysopidae	0.6034	0.7877	0.7950	0.8038	0.6336	0.2262	0.7010	0.8491	0.7007
Ichneumonidae	0.3778	0.6192	0.5075	0.6403	0.8188	0.3839	0.5548	0.5001	0.4352
Braconidae	0.7191	0.8996	0.8650	0.6988	0.6927	0.3684	0.8564	0.6348	0.7793
Family (Superfamily)	Corixidae	Chironomidae	Hydrophilidae	Scarabaeoidea	Staphylinidae	Anthicidae	Carabidae	Chrysopidae	Ichneumonidae
Chironomidae	0.3896
Hydrophilidae	0.4857	0.3698
Scarabaeoidea	0.5617	0.2510	0.4331
Staphylinidae	0.4627	0.4914	0.2352	0.6555
Anthicidae	0.3843	0.0417	0.0278	0.5241	0.6175
Carabidae	0.1641	0.0276	0.1098	0.4681	0.5135	0.4471
Chrysopidae	0.4651	0.1965	0.1645	0.7643	0.7208	0.5418	0.5375
Ichneumonidae	0.2546	0.0624	0.1084	0.4388	0.3475	0.3270	0.4485	0.5469
Braconidae	0.4645	0.4485	0.2976	0.5697	0.5839	0.3681	0.5068	0.6723	0.6176

).

From Table 6, it can be observed that the temporal niche breadth values greater than 4.0 are found in the following insect families or superfamilies: Tortricidae (4.8073), Pyraloidea (4.7367), Noctuidae (4.6916), Gelechioidea (4.6729), Plutellidae (4.5807), Braconidae (4.5534), and Geometridae (4.1659). Those with values between 3.5 and 4.0 include Staphylinidae (3.9115), Scarabaeoidea (3.6883), and Sphingidae (3.6408). This indicates that families such as Tortricidae have a high number of individuals, longer periods of activity, and make more efficient use of resources along the temporal axis. In contrast, Hydrophilidae and Chironomidae exhibit lower temporal niche breadths due to their aquatic life stages, which impose stricter environmental resource requirements and result in fewer individuals being observed under light traps. Additionally, among families with temporal niche breadth values exceeding 3.5, most are herbivorous Lepidoptera insects, except for the parasitic Braconidae and the omnivorous Staphylinidae and Scarabaeoidea. This suggests that vegetation is currently in good condition, but there is intense competition among herbivorous groups along the temporal resource axis.

The insect taxa with a spatial niche breadth greater than 4.5 include Sphingidae (5.7930), Cicadellidae (5.3959), Ichneumonidae (5.3792), Braconidae (5.3581), Geometridae (5.1978), Tortricidae (5.1802), Pyraloidea (5.1383), and Scarabaeoidea (5.0594). This indicates that Sphingidae are abundant, have a wide range of activities, and make relatively full use of spatial resources. Among these taxa, except for Ichneumonidae and Braconidae, which are parasitic groups, other taxa are primarily phytophagous insects. This suggests that at this stage, vegetation is relatively well developed, and phytophagous groups exhibit strong competition along the spatial resource axis. Taxa such as Corixidae and Chironomidae have aquatic life stages and therefore have higher environmental resource requirements. Their lower individual numbers under light traps result in their spatial niche breadth being at a relatively low level.

Among the common families (or superfamilies) of insects, those with a spatiotemporal niche breadth greater than 20.0 include Noctuidae (25.0212), Tortricidae (24.9028), Braconidae (24.3976), Pyraloidea (24.3386), Geometridae (21.6535), Sphingidae (21.0912), and Gelechioidea (20.9617). This indicates that they have long activity periods, wide distribution ranges, and make efficient use of spatiotemporal niche resources. In contrast, Hydrophilidae, Chironomidae, and Corixidae have shorter activity periods, narrower distribution ranges, and lower levels of spatiotemporal resource utilization.

3.2.2. Niche Overlap of Common Insect Families (or Superfamilies) in the Habahu Nature Reserve

From Table 7, it can be observed that the spatiotemporal niche overlap among herbivorous groups is the highest between Noctuidae and Pyraloidea, with a value of 0.9272, indicating the strongest resource competition between these two groups. Other overlaps greater than 0.8 include the following: Noctuidae and Geometridae (0.8905), Noctuidae and Gelechioidea (0.8161), Sphingidae and Scarabaeoidea (0.8305), Geometridae and Gelechioidea (0.8540), Geometridae and Pyraloidea (0.8349), Geometridae and Miridae (0.8230), Gelechioidea and Tortricidae (0.8727), and Gelechioidea and Pyraloidea (0.8144). This suggests intense competition for spatiotemporal niche resources among these groups. In this study, the predatory groups include Carabidae and Chrysopidae. For Carabidae, the spatiotemporal niche overlap with herbivorous groups is relatively high with Noctuidae (0.7661), Pyraloidea (0.6763), and Cicadellidae (0.6670). This indicates that Carabid insects may exert stronger predation pressure on these three groups. For Chrysopidae, the overlap with herbivorous groups is relatively high with Miridae, Cicadellidae, Gelechioidea, Noctuidae, and Geometridae, suggesting that Chrysopid insects have stronger predation effects on these five insect groups. Additionally, this indicates that Chrysopids likely have a broader diet compared to Carabids. The parasitic groups in this study are Ichneumonidae and Braconidae. Ichneumonidae show a high spatiotemporal niche overlap only with the herbivorous Tortricidae (0.8188). In contrast, Braconidae exhibit high overlap values with Noctuidae, Geometridae, and Pyraloidea, at 0.8996, 0.8650, and 0.8564, respectively. This suggests that Braconidae may have a broader parasitic range. Despite their close evolutionary relationship, Ichneumonids and Braconids parasitize different primary host groups due to potential host differentiation, which contributes to greater stability within insect communities. Corixidae, Chironomidae, and Hydrophilidae all have aquatic life habits, resulting in relatively low spatiotemporal niche overlap with terrestrial groups. Chironomidae and Hydrophilidae are primarily herbivorous or detritivorous, while Corixidae prey on small animals such as Chironomidae larvae. The overlap values among these groups are relatively moderate, with Corixidae and Chironomidae at 0.3896, Corixidae and Hydrophilidae at 0.4857, and Chironomidae and Hydrophilidae at 0.3698. These values are relatively balanced, with little difference, likely due to their narrow niche breadths and the interplay of predation and competition relationships.

4. Discussion

Insect taxonomy remains a significant challenge in efforts to conserve insect diversity [23]. Interpreting specific quantitative changes in insect diversity at the species level requires substantial time, funding, and expertise. Zou et al. [24] pointed out that biodiversity at the family level can serve as a good indicator of insect diversity at the species level. In niche research, researchers have also begun using higher taxonomic levels to interpret the niche characteristics of insect communities. For example, at the group level, Du Chao et al. [25] studied the niches of major groups in kiwifruit orchards using taxa such as spiders, leafhoppers, stink bugs, parasitic wasps, and flies. At the order level, Han et al. [5] conducted research on insect communities in the Taihu wetland, while He et al. [6] compared the niche characteristics of terrestrial insects across four wetlands in Yinchuan, China. At the family level, Hou et al. [10] studied the niche characteristics of moth communities in the Manghe Macaque National Nature Reserve, and Men et al. [11] investigated the temporal niches of moths under artificial sea buckthorn forests using light traps. These studies, using higher taxonomic levels (groups, orders, and families), have effectively explained the spatiotemporal niche characteristics of insect communities in their respective regions.

The phototactic behavior of insects is driven by the visual physiological response of their compound eyes, and light trapping exploits the positive phototaxis of insects. The activity rhythms of insects attracted to light at night vary depending on species. For example, pyralid moths are more active in the early night, while noctuids are more active in the late night [26]. Most insects are attracted to light in the early night, with the highest diversity and abundance of insects captured within the first 1–2 h after sunset [27]. In the Habahu Nature Reserve, sunset during the study period occurred around 20:00, and the observation period was set from 21:00 to 21:30, within 1.5 h after sunset, ensuring the capture of most light-attracted species. However, this study missed the species active in other periods of the early night and the late night. Additionally, diurnal insect species were not included in observations. Future research should integrate both diurnal and nocturnal insect species and set different observation time periods to obtain a closer approximation of the spatiotemporal two-dimensional ecological niche characteristics of insect communities.

Niche breadth and overlap indices are currently mainly applied to study the mechanisms of interspecific competition and coexistence, the spatial tracking and control effects of natural enemies on prey, and niche differences among vector insects [26]. In this study, the spatiotemporal niche characteristics at the order level revealed that Lepidoptera had the largest niche breadth value along the temporal resource axis, indicating that Lepidoptera insects have the longest activity time. Hemiptera had the largest niche breadth value along the spatial resource axis, suggesting that Hemipteran insects are distributed most evenly across observation sites. Regarding spatiotemporal niche breadth values, Lepidoptera and Coleoptera ranked first and second, respectively, which is similar to findings from insect communities under light traps in the Taihu Lake wetlands and Xinyang tea plantations, where Lepidoptera and Coleoptera also accounted for the highest proportions of individuals [7,9]. Odonata had the smallest niche breadth, likely because they are primarily diurnal, and those observed under light traps might have been resting nearby and attracted by light interference appearing on screens [28]. The largest spatiotemporal niche overlap was between Coleoptera and Lepidoptera, suggesting a potentially strong competitive or predatory relationship between them [29,30]. The lowest overlap was between Odonata and Diptera, likely due to the diurnal activity of Odonata [28].

Among common families (or superfamilies), Tortricidae had the largest temporal niche breadth, while Sphingidae had the largest spatial niche breadth, indicating that Tortricidae has the longest annual activity period, and Sphingidae is the most evenly distributed across observation sites. Hydrophilidae and Chironomidae had smaller temporal niche breadths, possibly because Hydrophilidae are primarily univoltine, with adults mainly appearing in May, while Chironomidae adults of univoltine species are active in early spring, late autumn, or winter, and multivoltine species are active in spring, summer, and early autumn, with adult lifespans typically lasting 1–2 weeks or up to one month [31]. Corixidae had the smallest spatial niche breadth, likely due to wetlands comprising only 12.76% of the reserve’s total area, limiting their potential habitats. Families with spatiotemporal niche breadths greater than 20.0 included Noctuidae (25.0212), Tortricidae (24.9028), Braconidae (24.3976), Pyraloidea (24.3386), Geometridae (21.6535), Sphingidae (21.0912), and Gelechioidea (20.9617). The Lepidoptera groups in this study differed slightly from those in Hou et al. [10], where Geometridae, Pyralidae, Noctuidae, and Tortricidae had broader spatiotemporal niches, indicating differences in niche characteristics among insect communities in different reserve types. Yang et al. [32] demonstrated that Sphingidae, Noctuidae, Geometridae, and Pyralidae dominate nocturnal pollinating moths. The utilization of night-blooming plant resources may be one reason for the relatively broad spatiotemporal niches of Lepidoptera families such as Noctuidae, Pyralidae, Geometridae, and Sphingidae in the Habahu Nature Reserve. During the authors’ fieldwork, they observed behaviors such as Hyles livornica (Esper, 1780) visiting Amygdalus triloba (Lindl.) Ricker flowers (Figure 2) and Lygephila procax (Hübner, [1813]) visiting Sorbaria kirilowii (Regel) Maxim. flowers (Figure 3). The three groups with the lowest spatiotemporal niche breadths were all aquatic, indicating that Hydrophilidae, Chironomidae, and Corixidae have short activity times and limited distribution ranges, possibly due to the distance of light traps from wetland habitats and the small proportion of wetlands in the reserve.

Among the common families (or superfamilies), herbivorous groups showed high niche overlap, suggesting that during afforestation processes, scarce plant resources have led to intense competition among herbivorous insects. Therefore, monitoring herbivorous insect populations should be intensified to protect these hard-earned forested areas. The overlap between Chrysopidae and Braconidae with herbivorous groups is relatively high, which warrants further investigation to explore which species within Chrysopidae and Braconidae are suitable for controlling major pest populations in protected areas. Although this study explored ecological niche characteristics at the family (or superfamily) level, it could not reveal predation or parasitic relationships between groups and somewhat overlooked various environmental factors. Therefore, future research should delve into genus- or species-level analyses while integrating diverse environmental factors to analyze insect community niches from both macro- and micro-perspectives.

5. Conclusions

This study on the spatiotemporal niche characteristics of insect communities under lamps in the Habahu National Nature Reserve revealed significant variations in niche breadth and overlap across taxa, reflecting their adaptive resource utilization in this semi-arid ecosystem. At the order level, Lepidoptera, Coleoptera, and Hemiptera exhibited the largest spatiotemporal niche breadths, with Lepidoptera dominating temporally and Hemiptera spatially, while Odonata consistently showed the narrowest niches. High niche overlap between Coleoptera and Lepidoptera indicated resource competition or shared preferences, whereas minimal overlap in Odonata and Diptera suggested niche divergence. Among families (or superfamilies), Noctuidae demonstrated the broadest temporal and spatiotemporal niches, while Sphingidae led spatially. Notably, interactions between herbivores, predators, and parasites—such as Noctuidae–Pyraloidea, Miridae–Chrysopidae, and Noctuidae–Braconidae—highlighted ecological relationships critical for community dynamics. These findings underscore the potential of Chrysopidae (predatory) and Braconidae (parasitic) as biological control agents, providing a theoretical foundation for integrated pest management strategies in conserving this unique desert grassland–wetland ecosystem.