Innate Host Habitat Preference in the Parasitoid Diachasmimorpha longicaudata: Functional Significance and Modifications through Learning

Abstract

Parasitoids searching for polyphagous herbivores can find their hosts in a variety of habitats. Under this scenario, chemical cues from the host habitat (not related to the host) represent poor indicators of host location. Hence, it is unlikely that naïve females show a strong response to host habitat cues, which would become important only if the parasitoids learn to associate such cues to the host presence. This concept does not consider that habitats can vary in profitability or host nutritional quality, which according to the optimal foraging theory and the preference-performance hypothesis (respectively) could shape the way in which parasitoids make use of chemical cues from the host habitat. We assessed innate preference in the fruit fly parasitoid Diachasmimorpha longicaudata among chemical cues from four host habitats (apple, fig, orange and peach) using a Y-tube olfactometer. Contrary to what was predicted, we found a hierarchic pattern of preference. The parasitism rate realized on these fruit species and the weight of the host correlates positively, to some extent, with the preference pattern, whereas preference did not correlate with survival and fecundity of the progeny. As expected for a parasitoid foraging for generalist hosts, habitat preference changed markedly depending on their previous experience and the abundance of hosts. These findings suggest that the pattern of preference for host habitats is attributable to differences in encounter rate and host quality. Host habitat preference seems to be, however, quite plastic and easily modified according to the information obtained during foraging.

Diachasmimorpha longicaudata as Biological Control agent of the Mediterranean fruit fly, Ceratitis capitata: biotic and abiotic factors affecting its implementation in citrus crops of the Mediterranean basin

“…In fact, the parasitism percentage and fertility were higher in peach, cementine and orange than on apple. This was the same for Segura et al (2016) and in contradiction with the results obtained by Leyva et al (1991) and Ovruski et al (2012) longicaudata, at least not an association that completely explains the preference for host habitats.…”

“…Moreover, we have determined a link between host fruit preference parasitism rate and fertility in a similar way as determined by Segura et al (2016) but of opposite sign to Leyva et al (1991) and Ovruski et al (2012). With our focal point control trials, we obtained 30-63% of medfly population reduction (Table 3.6), that corresponds to a higher parasitism rate when compared to laboratory conditions either obtained by us or by other researchers.…”

“…However, the texture of the fruit is known to affect the movements of larvae inside host and as consequence the quantity and the quality of the cues derived from each one. Our results revealed that D. longicaudata is able to detect its host in different host fruits and can parasitize and produce new generations in all tested host fruits indicating that it can be released in different crop productions and including apple, orange, clementine and peach as well as fig, guava, grapefruit, and mango as proved by Carrasco et al (2005) , Quilici and Rousse (2012) and Segura et al (2016 …”

“…By the use of the olfactometer we have determined that D. longicaudata was significantly attracted to C. capitata infested fruits compared to healthy ones, according to the previous findings using C. capitata or A. ludens as hosts (Duand and Messing 2000;Segura et al 2012). And respect to the fruit host, we had determined a sequential preference of host as peach > clementines > oranges over apples, being apples the less attractive among the tested fruits as also recorded by Segura et al (2016).…”

Plasticidade da aprendizagem de Diachasmimorpha longicaudata (Hymenoptera: Braconidae) associada a voláteis de frutos e óleos essenciais

“…Saleh & Chittka (2006) e Benelli et al (2014) realizaram estudos com braconídeos e constataram mudanças de comportamento através de aprendizagem olfativa. Dentre os braconídeos, Biosteres arisanus (Sonan, 1932), Psyttalia concolor (Szépligeti, 1910) e D. longicaudata são algumas das espécies que apresentaram evidências de aprendizagem (Dukas & Duan, 2000;Canale et al, 2014;Segura et al, 2007Segura et al, , 2016. Portanto, o conhecimento dos mecanismos que intermediam a comunicação química e a interação tritrófica entre D. longicaudata, inseto herbívoro e fruto, como a influência do hospedeiro de origem e da aprendizagem no comportamento de busca, podem resultar em práticas e produtos que favoreçam tanto o controle biológico natural quanto o aplicado.…”