Reproductive success of Trypoxylon (Trypargilum) lactitarse (Hymenoptera: Crabronidae) in a fragmented landscape

Grayce Kelly Costa Oliveira,Marcos Antonio Da Silva Elias,Leonardo Lima Bergamini,Edivani Villaron Franceschinelli

doi:10.1590/1678-4766e2020004

Grayce Kelly Costa Oliveira, Marcos Antonio Da Silva Elias + Show 2 more

Open Access

https://doi.org/10.1590/1678-4766e2020004

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Abstract

ABSTRACT Fragmentation of natural vegetation often implies a reduction in local species richness and abundance. The resources used by bees and wasps for feeding and nesting are distributed quite irregularly in fragmented environments, which influences their foraging behavior, occurrence patterns and reproductive success. The objective of the present work was to determine if the size of native vegetation remnants influences the reproductive success of the solitary wasp species Trypoxylon (Trypargilum) lactitarse Saussure, 1867. Trap-nests were established along the edges of forest fragments of different sizes located in municipalities in the central region of the state of Goiás, Brazil. The nests were used to quantify nesting rate, number of cells with larvae, survival of larvae, proportion of nests attacked by parasitoids, and size of hatched adults. The foundation rate of trap-nests was greater in large fragments, whereas the mean number of cells per nest, parasitoidism rate, larval survival and sex ratios, and size of hatched adults did not differ between large and small fragments. Therefore, it appears that fragment size influences the survival or permanence of adults more so than it does that of the larvae in the studied fragments. There are two possible explanations for the difference in the foundation rate: 1) each female founds, in average, the same number of nests in small and large fragments, but the number of females is lower in the smaller fragments; 2) females have the capacity to provision several nests, but in the larger areas each female founds more nests than in smaller areas. However, it is necessary future studies to differentiate these two hypotheses.

Highlights

Trap-nests placed along the border of large fragments had more nests and occupied cells than those along the border of small fragments
The data obtained in the present study verified greater nesting along the borders of large fragments than small fragments, which can be explained by the foundation rate increasing with increasing fragment area (z = 8.189, p < 0.001; Fig. 4)
The results of the present study showed that nesting occurred with greater intensity along the borders of the large fragments; that is, more nests were founded in larger than smaller fragments

Summary

Introduction

Dessa forma, o objetivo deste trabalho foi verificar se o tamanho das áreas de remanescentes de vegetação nativa interfere no sucesso reprodutivo de uma espécie de vespa solitária Trypoxylon (Trypargilum) lactitarse Saussure, 1867. Insects are under increasing pressure from anthropogenic factors, such as loss of natural habitat, ecosystem fragmentation and agricultural intensification (Potts et al, 2006; Brittain et al, 2010). Adults are commonly found in flowers and are potential pollinators (Bohart Menke, 1976) These wasps are solitary and predatory, supplying their nests with different species of spiders and insects. Wasp and bee diversity is known to be greater in continuous forests and larger fragments (Morato & Campos, 2000), whereas their species composition differs between continuous areas and altered habitats. The abundance of Trypoxylon figulus, for example, was found to be greater at edges than within forests in Switzerland (Coudrain et al, 2013)

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