Viruses rely on widespread genetic variation and large population size for adaptation. Large DNA virus populations are thought to harbor little variation though natural populations may be polymorphic. To measure the genetic variation present in a dsDNA virus population, we deep sequenced a natural strain of the baculovirus Autographa californica multiple nucleopolyhedrovirus. With 124,221X average genome coverage of our 133,926 bp long consensus, we could detect low frequency mutations (0.025%). K-means clustering was used to classify the mutations in four categories according to their frequency in the population. We found 60 high frequency non-synonymous mutations under balancing selection distributed in all functional classes. These mutants could alter viral adaptation dynamics, either through competitive or synergistic processes. Lastly, we developed a technique for the delimitation of large deletions in next generation sequencing data. We found that large deletions occur along the entire viral genome, with hotspots located in homologous repeat regions (hrs). Present in 25.4% of the genomes, these deletion mutants presumably require functional complementation to complete their infection cycle. They might thus have a large impact on the fitness of the baculovirus population. Altogether, we found a wide breadth of genomic variation in the baculovirus population, suggesting it has high adaptive potential.

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In polyandrous species, competition between males for reproduction goes on after copulation via the competition of their ejaculates for the fertilisation of female oocytes, it is called sperm competition. Different models of sperm competition predict adaptative plasticity of males in the production and allocation of their spermatozoa. These predictions were tested in the black soldier fly (BSF) Hermetia illucens, a farmed insect whose biology is little known despite its economic interest for bioconversion and as an animal feed. Two manipulations were carried out to modify the risks of sperm competition perceived by the males. The first consisted of placing adult males in different social contexts (alone or in groups of 10) and then measuring their sperm production. The second took place at the beginning of the copulation; pairs were transferred to different contexts of risk of sperm competition (empty cages, cages containing 10 males or cages containing 10 females), then the spermathecae of the females were collected in order to count the number of spermatozoa allocated by the males. Males in groups of 10 showed more spermatozoa in their seminal vesicles than males alone. Regarding sperm allocation, spermathecae of females in groups of 10 males, as well as those in groups of 10 females, had more spermatozoa than those placed in empty cages. We discussed this last result as a possibility that BSF males are not able to recognize the sex of their conspecifics. Copulation duration was not affected by these treatments, but was affected by the pair age. These manipulations of sperm competition risk showed that sperm production and allocation are dependent on social context in BSF. Males respond to the risks of sperm competition by a greater investment in sperm production and transfer. The existence of these mechanisms and their effects on reproduction underline the importance of studying the biology of farmed insects, for which fertility is essential.