Orchid bees (Hymenoptera, Apidae, Euglossini) are seasonal in Seasonal Semideciduous Forest fragments, southern Brazil

Vinicius Ortega Berno,Rodrigo Barbosa Gonçalves,Luiz Roberto Ribeiro Faria Jr.,Cleiton Margatto

doi:10.11606/1807-0205/2019.59.07

Abstract

Seasonal fluctuations in the abundance of orchid bees have already been reported. The variations in population dynamics may be expected to occur in more predictable and pronounced manners in environments with a clear distinction between rainy and dry seasons, where climatic variables are regarded to be good predictors of populational patterns. The main goal of this paper is to investigate the seasonality of males of orchid bees in fragments of Seasonal Semideciduous Forest in southern Brazil. Data comprise bait samples from five one-year periods on four forest fragments. The seasonality of species abundance was tested with circular statistics. Results suggest two phenological patterns, one for Eufriesea violacea (Blanchard), Eulaema nigrita Lepeletier and Euglossa cordata (Linnaeus), whose abundances are concentrated in late spring and early-middle summer and another for Euglossa fimbriata Moure with a tendency to be collected in middle-late summer and early autumn. These patterns are discussed, as well the possible driven factors, (i) the species life cycle and nesting behavior, (ii) synchrony with resource, and (iii) climate. We can postulate an important impact of climate change in local euglossine assemblage due to the small populations and marked seasonality.

Highlights

Phenology studies periodic life-cycle events over periods of time (Visser et al, 2010)
Results suggest two phenological patterns, one for Eufriesea violacea (Blanchard), Eulaema nigrita Lepeletier and Euglossa cordata (Linnaeus), whose abundances are concentrated in late spring and early-middle summer and another for Euglossa fimbriata Moure with a tendency to be collected in middle-late summer and early autumn
The main goal of this paper is to investigate the seasonality of males of orchid bees in fragments of Seasonal Semideciduous Forest in southern Brazil, answering the following question: is there any seasonal pattern in the abundance of euglossine species inhabiting these fragments?

Summary

Introduction

Phenology studies periodic life-cycle events over periods of time (Visser et al, 2010). Seasonal changes in the abundance of most tropical species are by far recognized as a main pattern in insect ecology (e.g., Wolda, 1978, 1980). Insect life history events are expected to be keyed to appropriate seasonal cycles in order to maintain ecological and biological viability of populations (Powell & Logan, 2005). Understanding seasonal contextualized adaptations requires a broad view of the effects of temporal, spatial, and resource patterns on their dynamics (Danks, 2007). Manifold factors drive seasonal population dynamics, both abiotic (e.g., temperature and pluviosity) and biotic (e.g., resource availability, predation, and parasitism) (Riedel et al, 2008; Tauber et al, 1986; Richards & Windsor, 2007; Turchin et al, 1999). Patterns of insect seasonality may vary for different species and habitats (Riedel et al, 2008), and can be perceived in distinct insect taxa, from species

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