Jack of All Trades, Master of All: A Positive Association between Habitat Niche Breadth and Foraging Performance in Pit-Building Antlion Larvae

Erez David Barkae,Zvika Abramsky,Ofer Ovadia,Inon Scharf,Zoltan Barta

doi:10.1371/journal.pone.0033506

Erez David Barkae, Zvika Abramsky + Show 3 more

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https://doi.org/10.1371/journal.pone.0033506

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Abstract

Species utilizing a wide range of resources are intuitively expected to be less efficient in exploiting each resource type compared to species which have developed an optimal phenotype for utilizing only one or a few resources. We report here the results of an empirical study whose aim was to test for a negative association between habitat niche breadth and foraging performance. As a model system to address this question, we used two highly abundant species of pit-building antlions varying in their habitat niche breadth: the habitat generalist Myrmeleon hyalinus, which inhabits a variety of soil types but occurs mainly in sandy soils, and the habitat specialist Cueta lineosa, which is restricted to light soils such as loess. Both species were able to discriminate between the two soils, with each showing a distinct and higher preference to the soil type providing higher prey capture success and characterizing its primary habitat-of-origin. As expected, only small differences in the foraging performances of the habitat generalist were evident between the two soils, while the performance of the habitat specialist was markedly reduced in the alternative sandy soil. Remarkably, in both soil types, the habitat generalist constructed pits and responded to prey faster than the habitat specialist, at least under the temperature range of this study. Furthermore, prey capture success of the habitat generalist was higher than that of the habitat specialist irrespective of the soil type or prey ant species encountered, implying a positive association between habitat niche-breadth and foraging performance. Alternatively, C. lineosa specialization to light soils does not necessarily confer upon its superiority in utilizing such habitats. We thus suggest that habitat specialization in C. lineosa is either an evolutionary dead-end, or, more likely, that this species' superiority in light soils can only be evident when considering additional niche axes.

Highlights

Habitat utilization spectrum is an important dimension of the ecological niche
If adaptation to an additional habitat entails a fitness loss in the former, species having a narrow spectrum of habitat utilization should perform better than those utilizing a wider range of habitats, but only within a narrower habitat spectrum
We report here on the results of an empirical study whose aim was to test for a negative association between habitat niche breadth and foraging performance

Summary

Introduction

Habitat utilization spectrum is an important dimension of the ecological niche. A broadly accepted explanation for the variation in niche breadth among closely related species along such central niche axes, is the existence of a trade-off between the ability of a species to utilize a wide range of resources and its performance when exploiting only one or a few of them [1,2,3,4,5,6]. Pit-building antlion species can greatly differ in their habitat niche breadth and preferred habitats. Antlions exhibit extensive variation in their preferences for soil/sand particle sizes ([16,17] see [18] for a comparison between antlions and wormlions). Despite their preferences for different soil types, antlions will sometimes construct pits in less desirable habitats, but because such pits are usually smaller, they can cause reductions in prey capture rate [12,19]

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