Climate Change and its Effects on the Chemical Ecology of Insect Parasitoids

Abstract

Over the course of evolutionary time, insect parasitoids have developed diverse strategies for using chemical compounds to communicate with various protagonists within their environment (i.e. conspecifi cs, their hosts, and the plants on which their hosts are living). Unravelling the evolutionary meaning of such chemical communication networks not only provides new insights into the ecology of these insects but also contributes to improving the use of parasitoids for the control of insect pests in biological control programmes. A book covering our current knowledge of the chemical ecology of insect parasitoids is therefore particularly timely and will appeal to a large number of potential readers worldwide, from university students to senior scientists. Internationally recognized specialists were invited to contribute chapters to this book, examining the main topics and exploring the most interesting issues in the fi eld of chemical ecology of insect parasitoids. The chapters are organized so as to present the most signifi cant knowledge and discoveries made over recent decades, and their potential uses in pest control.

Can we forecast the effects of climate change on entomophagous biological control agents?

“…On the one hand, insects using CO 2 to detect their food source or oviposition site (such as moths, fruit flies or hematophagous insects) can be directly affected . On the other hand, as described before, altered leaf chemistry and temperature can affect second and higher trophic levels in all possible ways . For instance, in aphids, even a single clone has been reported to display different responses to high CO 2 content, depending on the host plant .…”

Climate Change and Tritrophic Interactions: Will Modifications to Greenhouse Gas Emissions Increase the Vulnerability of Herbivorous Insects to Natural Enemies?

“…All of these studies have principally focused on parasitoids rather than on predators. Parasitoids, which are considered to be more specialists than predators, seem to be more able to detect the presence of herbivore-induced damage to plants through the perception of secondary metabolites released into the environment by the plant (Holopainen et al 2013). O 3 is more responsible for modifications to plant secondary metabolites and foliar composition than most other greenhouse gases, including CO 2 .…”

“…Under elevated CO 2 conditions, the release rates of glucosinolate-derived chemicals is increased (Bidart-Bouzat and Imeh-Nathaniel 2008), which could lead to an enhanced attraction of natural enemies. On the other hand, modifications to the ratios and the dilution of herbivore-induced volatiles due to degradation by air pollutants could disorientate natural enemies (Webster et al 2008, Holopainen et al 2013. Pinto et al (2007a, b) showed that the ability of parasitoid and predator species to locate host plants based on the perception of secondary plant metabolites was minimally affected under elevated O 3 conditions.…”

Language of plants: Where is the word?

“…The order of the C6 compound emissions after larval feeding activity may explain at least partially why Cotesia vestalis , a parasitoid of Plutella xylostella , prefers landing on damaged Brassica leaf tissue and first actively analyze the extension of damage, although the host larvae are available on the same leaf (Holopainen et al ). It is likely that emission of hexenal compounds from a damaged area may indicate the most recent damage and presence of host larvae nearby, while emissions dominated by ( Z )‐3‐hexenol and ( Z )‐3‐hexenyl acetate indicate damaged leaf, but not so fresh damage, thus possibly telling the parasitoid about lower probability to find a host larva.…”