Dinocampus coccinellae (Hymenoptera: Braconidae) is a generalist parasitoid wasp that parasitizes >50 species of predatory lady beetles (Coleoptera: Coccinellidae), with thelytokous parthenogeny as its primary mode of reproduction. Here we present the first high quality genome of D. coccinellae using a combination of short and long read sequencing technologies, followed by assembly and scaffolding of chromosomal segments using Chicago+HiC technologies. We also present a first-pass ab initio and a reference-based genome annotation, and resolve timings of divergence and evolution of (1) solitary behavior vs eusociality, (2) arrhenotokous vs thelytokous parthenogenesis, and (3) rates of gene loss and gain among Hymenopteran lineages. Our study finds (1) at least two independent origins of eusociality and solitary behavior among Hymenoptera, (2) two independent origins of thelytokous parthenogenesis from ancestral arrhenotoky, and (3) accelerated rates of gene duplications, loss, and gain along the lineages leading to D. coccinellae. Our work both affirms the ancient divergence of Braconid wasps from ancestral Hymenopterans and accelerated rates of evolution in response to adaptations to novel hosts, including polyDNA viral co-evolution.

Dinocampus coccinellae (Hymenoptera: Braconidae) is a generalist parasitoid wasp that parasitizes >50 species of predatory lady beetles (Coleoptera: Coccinellidae), with thelytokous parthenogeny as its primary mode of reproduction. Here we present the first high quality genome of D. coccinellae using a combination of short and long read sequencing technologies, followed by assembly and scaffolding of chromosomal segments using Chicago+HiC technologies. We also present a first-pass ab initio genome annotation, and resolve timings of divergence and evolution of (1) solitary behavior vs eusociality, (2) arrhenotokous vs thelytokous parthenogenesis, and (3) rates of gene loss and gain among Hymenopteran lineages. Our study finds (1) at least two independent origins of eusociality and solitary behavior among Hymenoptera, (2) two independent origins of thelytokous parthenogenesis from ancestral arrhenotoky, and (3) accelerated rates of gene duplications, loss, and gain along the lineages leading to D. coccinellae. Our work both affirms the ancient divergence of Braconid wasps from ancestral Hymenopterans and accelerated rates of evolution in response to adaptations to novel hosts, including polyDNA viral co-evolution.

Dinocampus coccinellae (Hymenoptera:Braconidae, Euphorinae) is a solitary, generalist Braconid parasitoid wasp of over fifty diverse species of coccinellid ladybeetles worldwide that reproduces through thelytokous parthenogenesis, an asexual process in which diploid daughters emerge from unfertilized eggs. Here we utilized a common garden and reciprocal transplant experiment using parthenogenetic lines of D. coccinellae presented with three different host ladybeetle species of varying sizes, across multiple generations to investigate heritability, plasticity, and environmental covariation of body size. Since unilineal (reared on same host species) lines restrict environmental variation on clones, we expected positively correlated parent-offspring parasitoid regressions, indicative of heritable size variation. Whereas multilineal (reared on different host species) lines would quantify phenotypic plasticity of clones reared in varying environments, we expected negatively correlated parent-offspring parasitoid regressions. Contrary to expectations, our results indicate (1) little heritable variation in body size, (2) strong dependence of offspring size on the host environment, (3) a consistent signal of size-host tradeoff wherein small mothers always produced larger offspring, and vice versa, independent of host environment. Our study offers support for a constrained fecundity advantage model of Cope's Law, wherein D. coccinellae maintains phenotypic plasticity in body size despite parthenogenetic reproduction.