DEVELOPMENT OF METHODS OF BREEDING WORK WITH INSECTS OF THE SPECIES HERMETIA ILLUCENS
Authors: Pestsov Georgiy V. , Prokudina Olga V. , Tretyakova Anastasia V. , Butenko Sergey A. 
Published: August 2023

Background. The insect Hermetia illucens (black soldier fly), is widely used for the disposal of food and agricultural waste. This is due to the omnivorous nature of the fly in relation to protein and carbohydrate foods and a fast reproductive cycle. The big problem of industrial cultivation of this insect is the degeneration of populations of the black soldier fly. When bred in captivity, due to the relatively small number of population, the degradation of key parameters, such as viability, fertility, productivity, etc. of H. illucens culture occurs. It is noted that during the first five generations, despite polygamy during crossing, the effect of harmful recessive alleles in a homozygous state manifests itself. Currently, the problem of degeneration of flies associated with inbred depression is solved by mass cultivation of large outbred populations in cages, with periodic reintroduction of producers from natural populations.

Purpose. Development of a method for crossing lines of Hermetia illucens flies for breeding, determining patterns of population development, as well as increasing their productivity and adaptive potential.

Materials and Methods. In selection work with the lines of the insect species H. illucens, individual crossing was used. Individual selections were made by selecting larvae and pupae by size and body weight. The crosses were carried out according to the scheme: one male and one female were placed in plastic containers while maintaining the required temperature and humidity. Eggs obtained from this pair of flies were placed on a nutrient substrate in a separate container, hatched larvae were cultured in isolation in the same container. During the growth process, the largest larvae and pupae from this population were selected. After the formation of adult individuals (images) of flies, they were examined, their sex was determined and again one male and one female were placed in a separate container. Thus, inbred lines of isofemale (descendants of one female) flies were obtained.

Results. We developed the method of individual crossing made it possible to trace the development of populations of flies obtained from one female and one male, to consider the patterns and changes in the population. The tendency of the degeneration of the fly population in inbred crosses was determined, in each subsequent generation there were fewer fertilized eggs and larvae. This is due to the fact that recessive lethal genes become homozygous and manifest their effect. Subsequent selections in each generation of the largest and most active larvae will create a population devoid of most lethal and harmful genes.

Conclusions. As a result of the research work carried out, it was possible to develop a method of individual crossing of males and females of the insect Hermetia illucens. It was determined that the time from oviposition onset to the maximum number of larvae occurs on 3-4th day after egg laying. With the crossing of close relatives, the tendency of the degeneration of the fly population was determined, in each subsequent generation there were fewer fertilized eggs and larvae. This is due to the manifestation of recessive lethals. Subsequent selections in each generation of the largest and most active larvae will create a population devoid of most lethal and harmful genes. Populations of inbred flies have stable characteristics for this species and, despite a decrease in the number of fertilized eggs in clutches, as well as a smaller number of larvae obtained from them, they have normal distribution of size and body weight, which allows selection for economically valuable traits.