English

J. Quinnell R.,Al Khalaf A.,G. Compton S.

doi:10.5897/ajar2014.8792

Abstract

Ambient temperatures influence many aspects of insect behavior and reproduction, and limit their distribution and abundance. Small, delicate insects such as the fig wasps (Agaonidae) that pollinate fig trees rapidly succumb to heat stress when outside figs. We compared survivorship and reproductive success of the fig wasp Kradibia tentacularis pollinator of the Asian fig tree Ficus montana in three glasshouses maintained at different temperatures during the brief period when foundress females are laying their eggs after their entry into figs (means of 17, 21 and 27°C, respectively). This temperature range had no significant effect on speed of foundress death, or their likelihood of re-emergence. Similarly, fig wasp offspring production were unaffected by temperatures at the time of oviposition in male figs, as was seed production in female figs, although the proportion of failed galls changed marginally. The range of temperatures to which the fig wasps were exposed reflected conditions under a tropical forest canopy and their general lack of responsiveness suggests that the relatively buffered environment within their host figs means that only extreme temperature conditions will influence them once they have entered the plant. Key words: Agaonidae, climate change, Ficus, oviposition, sex ratio, thermal tolerance.

Highlights

Temperature is probably the abiotic factor with the largest single influence on the distribution and abundance of insects (Andrewartha and Birch, 1954).Predicted changes in climate suggest that many insect species will be exposed to higher median temperatures and extreme temperature events in the future, with consequences for their population dynamics, distribution and evolution (Walters, 2012; Van Velzen et al, 2013)
Species involved in obligate mutualisms are likely to be responsive to climate change, because of the strong interdependency between partners (Kiers et al, 2010; Colwell et al, 2012; Gilman et al, 2012)
The approximately 800 described species of fig trees are found mainly in tropical and subtropical regions, in habitats ranging from rainforests to deserts (Berg and Corner, 2005).They are all pollinated exclusively by host specific fig wasps (Agaonidae), with each fig tree species dependent on one or a small number of fig wasp species

Summary

Introduction

Temperature is probably the abiotic factor with the largest single influence on the distribution and abundance of insects (Andrewartha and Birch, 1954). Predicted changes in climate suggest that many insect species will be exposed to higher median temperatures and extreme temperature events in the future, with consequences for their population dynamics, distribution and evolution (Walters, 2012; Van Velzen et al, 2013). Species involved in obligate mutualisms are likely to be responsive to climate change, because of the strong interdependency between partners (Kiers et al., 2010; Colwell et al, 2012; Gilman et al, 2012). Fig trees (Ficus, Moraceae) are an example of obligate mutualists that have very wide ecological significance; more species vertebrates feed on their fruits than on those of any other plants (Shanahan et al, 2001). The approximately 800 described species of fig trees are found mainly in tropical and subtropical regions, in habitats ranging from rainforests to deserts (Berg and Corner, 2005).They are all pollinated exclusively by host specific fig wasps (Agaonidae), with each fig tree species dependent on one or a small number of fig wasp species.

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