Dietary niche variation and its relationship to lizard population density

Novosolov, Maria; Rodda, Gordon H.; Gainsbury, Alison M.; Meiri, Shai

doi:10.1111/1365-2656.12762

Cited by 19 publications

(14 citation statements)

References 90 publications

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“…Although niche specialization can be high in insular habitats due to the restricted amount of resources [62], species can coexist through the niche segregation into multidimensional axes such as space, time, strata, or diet [37]. The three wasp species coexisting in the oases of Baja California Peninsula are displaying differential food specialization, which is probable the result of isolation processes that have led to evolutionary selective pressures.…”

Section: Discussionmentioning

confidence: 99%

Disentangling the coexistence strategies of mud-daubing wasp species through trophic analysis in oases of Baja California peninsula

2019

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Species within the same trophic level show different strategies to avoid competition. Among these mechanisms, differences in body size, spatio-temporal segregation, and diet preference often leads to a niche partitioning. Nonetheless, little attention on coexisting predatory insects and their network interactions has been paid. In this study, we analyzed the strategies to avoid competition among three sympatric mud-daubing wasps of the genus Trypoxylon (Hymenoptera: Crabronidae) in oases and their surrounding xeric area from the Baja California peninsula, Mexico. We compared the prey richness, composition and proportion of spider guilds that were captured by the wasps. We tested whether the differences in wasp body size explained the niche breadth, niche overlap and the size of spider prey. We assessed the spider-wasp interactions through a network analysis. With the use of trap-nests, we collected 52 spider species captured by the wasps. Both the guild and species composition of preyed spiders was different between the three wasp species. Differential proportions in the capture of spider guilds and a little diet overlap were found among the wasp species. We found that the wasp body size was positively correlated with prey size, but it was not a proxy of niche breadth. Moreover, the largest wasp species was able to nest in both mesic and xeric habitats, while the two smaller species were restricted to the oases. This study reveals that the diversity of spiders in oases of Baja California peninsula is crucial to maintain highly specialized oasis-dependent wasp species. The niche partitioning between mud-daubing wasps can be shaped by their inherent body size limitations and hunting strategies through foraging specialization for specific spider guilds. Food selection and slight differences in body size reduce competition and allow the coexistence of sympatric wasps. Our study is the first approach exploring the interaction networks between mud-daubing wasps and their spider preys, highlighting new insights into the morphological and ecological factors that shape antagonistic interactions, and allow the coexistence of predators in deserts.

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Section: Discussionmentioning

confidence: 99%

Disentangling the coexistence strategies of mud-daubing wasp species through trophic analysis in oases of Baja California peninsula

2019

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“…A relatively lower interspecific competition in lava lizards (single island species), compared to Jamaican Anolis lizards (four syntopic species), might create a weak selective pressure on Galápagos individuals to diverge in the use of food resources (niche variation hypothesis) (Bolnick et al. 2010; but see Novosolov et al. 2018).…”

Section: Discussionmentioning

confidence: 99%

“…Frugivory by lizards is particularly common on islands. Insular lizards are more likely to consume fruits, since population densities tend to be higher whereas interspecific competition and predator pressure tend to be lower than on the mainland (Olesen and Valido 2003; Novosolov et al. 2018).…”

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confidence: 99%

Small size does not restrain frugivory and seed dispersal across the evolutionary radiation of Galápagos lava lizards

Hervías‐Parejo¹,

Heleno

Rumeu³

et al. 2018

Current Zoology

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Frugivory in lizards is often assumed to be constrained by body size; only large individuals are considered capable of consuming fruits, with the potential of acting as seed dispersers. However, only one previous study has tested the correlation of frugivory with body and head size at an archipelago scale across closely related species. All nine lava lizards (Microlophus spp.) were studied on the eleven largest Galápagos islands from 2010 to 2016 to investigate whether frugivory is related to body and head size. We also tested whether fruit abundance influences fruit consumption and explored the effect of seed ingestion on seedling emergence time and percentage. Our results showed that across islands, lava lizards varied considerably in size (64–102 mm in mean snout–vent length) and level of frugivory (1–23%, i.e., percentage of droppings with seeds). However, level of frugivory was only weakly affected by size as fruit consumption was also common among small lizards. Lava lizards consumed fruits throughout the year and factors other than fruit abundance may be more important drivers of fruit selection (e.g., fruit size, energy content of pulp). From 2,530 droppings, 1,714 seeds of at least 61 plant species were identified, 76% of the species being native to the Galápagos. Most seeds (91%) showed no external structural damage. Seedling emergence time (44 versus 118 days) and percentage (20% versus 12%) were enhanced for lizard-ingested seeds compared to control (uningested) fruits. De-pulping by lizards (i.e., removal of pulp with potential germination inhibitors) might increase the chances that at least some seeds find suitable recruitment conditions. We concluded that lizards are important seed dispersers throughout the year and across the whole archipelago, regardless of body size.

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“…2014) and was a reasonable hypothesis here in this study, recent empirical evidence from other studies does not consistently support this hypothesis. For example, dietary niche breadth in lizards is thought to be a function of the variety of resources available in the environment and not associated changes in the density of lizards (i.e., not associated with changes in intraspecific competition for resources) (Novosolov et al. 2017).…”

Section: Discussionmentioning

confidence: 99%

Sex, size, and prey caloric value affect diet specialization and consumption of an invasive prey by a native predator

2018

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Escaping the control of natural enemies is thought to heavily influence the establishment success and impact of non-native species. Here, we examined how the profitability of alternative prey in combination with the presence of a competitor and predator aggressive behavior explain individual differences in diet specialization and the consumption of the invasive green porcelain crab Petrolisthes armatus by the native mud crab predator Panopeus herbstii. Results from bomb calorimetry estimates show that invasive P. armatus has high caloric value relative to alternative native prey. Laboratory assays indicated that specialization and consumption of invasive P. armatus was mostly exhibited by large, female P. herbstii, but the presence of a competitor and predator aggressiveness did not influence diet and the consumption of P. armatus. Thus, intrinsic factors (e.g., sex and body size) seem to explain consumption of P. armatus and dietary specialization in P. herbstii, more generally. Although there are still many predator individuals that do not consume P. armatus, the proportion of individuals that have begun to specialize on P. armatus suggests that for some, it has become more profitable relative to alternative native prey. Given the high caloric value of P. armatus, we suggest that it is likely that differences in the cost of its consumption, including attack, capture, and handling times relative to alternative prey, determine its net profitability to individual predators.

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Dietary niche variation and its relationship to lizard population density

Cited by 19 publications

References 90 publications

Disentangling the coexistence strategies of mud-daubing wasp species through trophic analysis in oases of Baja California peninsula

Disentangling the coexistence strategies of mud-daubing wasp species through trophic analysis in oases of Baja California peninsula

Small size does not restrain frugivory and seed dispersal across the evolutionary radiation of Galápagos lava lizards

Sex, size, and prey caloric value affect diet specialization and consumption of an invasive prey by a native predator

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