Food-searching in parasitoids: the dilemma of choosing between 'immediate' or future fitness gains
Food-searching in parasitoids: the dilemma of choosing between 'immediate' or future fitness gains
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DOI：
10.1002/9780470696200
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发表时间：
2008-04
期刊：
影响因子：
--
通讯作者：
C. Bernstein;M. Jervis
中科院分区：
文献类型：
--
作者：
C. Bernstein;M. Jervis
Many parasitoid wasps and flies feed habitually on sugar-rich foods, consuming nectar and/or homopteran honeydew in the wild, and substitutes such as diluted honey in the laboratory. Consumption of these ‘non-host foods’ generally results in increases in female life expectancy, dispersal capacity, and realized fecundity. Typically in the wild, hosts and food sources are spatially separate. A female parasitoid therefore faces a choice as to which of the two types of resource she should forage for. Foraging for hosts will increase the likelihood of her obtaining ‘immediate’ fitness gains, but it will decrease her life expectancy. Foraging for food will postpone egg-laying to a later stage in adult life (constituting an ‘immediate’ reproductive opportunity cost), and will also incur energetic and mortality costs. However, it will increase opportunities to locate hosts in the future. From the standpoint of the fitness consequences of parasitoid foraging decisions, the exploitation of non-host foods is thus a highly interesting topic, posing the question of how females should forage so as to optimize trade-offs with respect to the use of both time and metabolic resources, and also mortality risks. In order to understand how such optimization might be achieved, we review current knowledge regarding resource ‘income’ and ‘capital’ used by females of parasitoid species that feed solely on non-host materials. Host-foraging versus non-host food-foraging, in such insects, has previously been modeled by means of stochastic dynamic programming. Using this technique, we model the behavioral scenario in which hosts and food patches are concurrently available but spatially separate. We focus initially on the egg maturation strategy of pro-ovigeny (in which all eggs are mature upon female emergence), but then examine the alternative and more common strategy of synovigeny (some eggs are immature). We discuss briefly the implications of variation in food availability for host population dynamics, and relate these to biological control scenarios. Finally, we identify promising avenues of future research. 9781405163477_4_007.qxd 03/09/2007 04:08PM Page 129
