Insect oviposition plasticity in response to host availability: the case of the tephritid fruit fly Bactrocera dorsalis

Authors


Yijuan Xu, Laboratory of Insect Ecology, College of Natural Resources and Environment, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China. E-mail: xuyijuan@yahoo.com

Abstract

1. Insect oviposition behaviour is ecologically and physiologically plastic. For tephritid fruit flies, Bactrocera dorsalis Hendel, host availability varies spatially and temporally. Females are expected to adopt adaptive oviposition strategies to maximise lifetime reproductive fitness, including survival. Bactrocera dorsalis oviposition tactics in response to different host availabilities were investigated.

2. This study includes three treatments: (i) variable host densities (host density varied according to a fixed cycle from day to day over values of 1, 5, 10 and 20 hosts per cage), (ii) a fixed high host density (20 hosts per cage), and (iii) a fixed low host density (1 host per cage).

3. Daily egg-laying number per female over the course of 27 days was entirely independent of host density and highly dependent on female age. As host availability increased, females accepted significantly more hosts, generally laid small egg clutches, and more broadly distributed the eggs.

4. Tephritid fruit flies adaptively adjusted egg clutches in ways that reflected the variability of host availability. Egg- and time-limitation constraints appeared to drive these adjustments. Female egg maturation was triggered by oviposition activity and reflected marked lifetime trade-offs. Such strategies involved specific time schedules for egg laying.

5.This study defined the oviposition plasticity of the tephritid fruit fly. These results have general implications for the behavioural ecology of insect herbivores and parasitoids.

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