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

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.

Decline of native bees (Apidae: Euglossa) in a tropical forest of Panama

“…The species we collected in our study varied in abundance by almost three orders of magnitude (Table I) and showed different patterns of decline (Figure 3), accounting for the strong effect of species identity in our analysis of abundance, but no species showed an increase in abundance over the 5 years of the study. We believe that the declines we report are not the result of our sampling, given that phenology of orchid bees varies between species (Margatto et al 2019) and trends in abundance vary between species in our study (Figure 3). Roubik (2001) suggests that at least 4 years of data are necessary to distinguish long-term population trends from year-to-year variation.…”

Diversity and distribution of orchid bees (Hymenoptera: Apidae, Euglossini) in Belize

“…Fourth, we sampled only October–March, though our sample dates included both the late-wet (Dec–Jan) and early-dry (Feb) seasons ( Climate Change Knowledge Portal, 2018 ). This interval spanned a good part of the range of seasonal climatic variation in Belize, but we may have missed species inactive as adults or lower in abundance due to the well-documented seasonality of some orchid bees ( Janzen et al, 1982 ; Ackerman, 1983b ; Roubik & Ackerman, 1987 ; Knoll, 2016 ; Nemésio, Santos & Vasconcelos, 2015 ; Costa & Francoy, 2017 ; Margatto et al, 2019 ; Bravo et al, 2022 ). However, most euglossines are active as adults through most of the year ( Roubik & Hanson, 2004 ; see also Janzen et al, 1982 ), and Ackerman (1983b) found that species composition and relative abundance at lowland sites in Panama were comparable across seasons.…”

Distribution patterns of orchid bees in xeric and mesic habitats on a tropical mountaintop

“…aratingae ). The response to seasonality can be species‐specific (Pinto et al, 2019) because some euglossine species are univoltine and go into diapause, waiting for suitable environmental conditions such as climate or flowers (Kimsey, 1982; Margatto et al, 2019; Willmer, 2014). Regions with a strongly seasonal climate, such as Serra do Cipó, are capable of producing well‐defined temporal patterns of euglossines (Santos et al, 2020).…”