Newly Woody Artificial Diet Reveals Antibacterial Activity of Hemolymph in Larvae of Zophobas atratus (Fabricius, 1775) (Coleoptera: Tenebrionidae)
by
, and
Alexander Kuprin
1,*,
Vladislava Baklanova
1,
Maria Khandy
1,
Andrei Grinchenko
2,3 and
Vadim Kumeiko
2,3 1
Federal Scientific Center of the East Asia Terrestrial Biodiversity, Far East Branch, Russian Academy of Sciences, Vladivostok 690022, Russia
2
School of Medicine and Life Sciences, Far Eastern Federal University, Russky Island, Vladivostok 690091, Russia
3
A.V. Zhirmunsky National Scientific Center of Marine Biology, Far East Branch, Russian Academy of Sciences, Vladivostok 690041, Russia
*
Author to whom correspondence should be addressed.
Insects 2024, 15(6), 435; https://doi.org/10.3390/insects15060435
Submission received: 8 May 2024
/
Revised: 5 June 2024
/
Accepted: 6 June 2024
/
Published: 8 June 2024
(This article belongs to the Special Issue Insect Rearing: Reserve Forces with Commercial and Ecological Values)
Simple Summary
Currently, the optimization of mass rearing conditions for insects is a matter of highly applied and fundamental relevance since insects can be used as a source of protein in feed and feed supplements for farm animals as well as a source of antibacterial compounds for drug development and various insect research activities in laboratory conditions. The quantity and quality of the consumed feed has an effect on insect growth rate, duration of development, body weight, ability to spread, and survival, as well as on the mating success rate and total egg production of females. Suboptimal nutrition, growth, and development can affect beetle viability. We developed an artificial fungi-based diet for rearing an insect group adapted to life in wood and using it as one of their food sources and tested the effect of this diet on various parameters of the insects’ development and their immunity. Zophobas atratus (Fabricius, 1775) (Coleoptera: Tenebrionidae) was chosen as a model species (representative of this group of insects). Based on the parameters of development at all stages of Z. atratus and screening of hemolymph antibacterial activity of their larvae, we showed that the cultivation method we developed shortens the development time of beetles and strengthens their immunity.
Abstract
The rearing of saproxylic insects in laboratory conditions is an important task for studying the biology of insects. Through understanding nutritional needs, it is possible to optimize beetle rearing in laboratory conditions. In this study, an artificial fungi-based diet (FD) was developed for the cultivation of the darkling beetle Zophobas atratus (Fabricius, 1775) (Coleoptera: Tenebrionidae) in laboratory conditions as a model object for studying the biology of saproxylophagous beetles. To assess the influence of the diet, a number of physiological parameters were measured, including development time, body size, and weight of all stages of the beetle’s life cycle, as well as its immune status. The immune status of Z. atratus was assessed on the basis of larval hemolymph antibacterial activity against six different bacterial strains assessed using disk-diffusion and photometric tests. Our findings show that the FD reduces development time and boosts the immune status as compared to beetles reared on a standard diet (SD). Samples from FD-reared larvae had pronounced antibacterial activity as compared to samples from SD-reared larvae. This work is of fundamental importance for understanding the correlations between nutrition and development of saproxylic Coleoptera and is the first report on immune status regulation in this group of insects.
