Venom is beneficial but not essential for development and survival of Nasonia

Abstract

Parasitoid wasps sting and inject venom in arthropod hosts, which alters host metabolism and development while keeping the host alive for several days, presumably to induce benefits for the parasitoid young.Here we investigate the consequences of host envenomation on development and fitness of wasp larvae in the ectoparasitoid , by comparing wasps reared on live unstung, previously stung, and cold-killed hosts. Developmental arrest and suppression of host response to larvae are major venom effects that occur in both stung and cold-killed hosts, but not unstung hosts; while cold-killed hosts lack venom effects that require a living host. Thus, cold-killed hosts mimic some of the effects of venom, but not others.Eggs placed on live unstung hosts have significantly higher mortality during development, however successfully developing wasps from these hosts have similar lifetime fecundity to wasps from cold-killed or stung hosts. Therefore, although venom is beneficial, it is not required for wasp survival.While wasps developing on cold-killed versus stung hosts have similar fitness, multiple generations of rearing on cold-killed hosts results in significant fitness reductions of wasps.We conclude that the largest benefits of venom are induction of host developmental arrest and suppression of host response to larva (e.g. immune responses), although more subtle benefits may accrue across generations, or under stressful conditions.

The Diversity of Venom: The Importance of Behavior and Venom System Morphology in Understanding Its Ecology and Evolution

“…While ectoparasitoid wasps use their venom to preserve food for their young, endoparasitoid wasps use their venom to transform organisms into a new habitat, or nurseries, for their offspring to live in and feed on when they hatch [34]. To achieve this, endoparasitoids such as Nasonia vitripennis inject venom into the host prior to oviposition to selectively suppress parts of the immune system, arrest development, and manipulate the internal nutritional environment [35,36].…”

Variation in the Venom of Parasitic Wasps, Drift, or Selection? Insights From a Multivariate QST Analysis

“…However, geographic variation of parasitoid virulence factors has only been little studied to date although most adaptive evolutionary constraints are determined at this level of organization (Kawecki and Ebert, 2004;Biron et al, 2006;Wagner, 2012). In many parasitoids, the virulence factors are mainly contained in the venom injected into the host at the time of oviposition, which results in the inhibition of the immune system of the host as well as the regulation of its physiology, or behavior, thus optimizing the development of the parasitoid offspring (Poirié et al, 2009(Poirié et al, , 2014Mrinalini et al, 2014;Moreau and Asgari, 2015;Martinson and Werren, 2018;Walker et al, 2018).…”

Rapid and differential evolution of the venom composition of a parasitoid wasp depending on the host strain

“…[1][2][3]) but also by environmental conditions [4]. This question remains however largely unaddressed for parasitoid waspsinsects that develop at the expense of their arthropod host, leading to its death -although they rely primarily on the injection of venom during oviposition to overcome the immune defenses of the host (reviewed in [5][6][7]) and optimize the development of their offspring [8,9]. Parasitoid wasps act as important regulators of insect species communities in the field, and are thus also widely used as biological control agents.…”