Temporal variation in the abundance of Orchid Bees (Hymenoptera: Apidae) in a Neotropical Hygrophilous Forest

Abstract

Although bees are important pollinators in several ecosystems around the world, studies on bee diversity in hygrophilous forests are scarce. This type of vegetation is restricted to permanently wet soils and, therefore, has particular floristic, structure and physiognomy. The goal of the present study was to inventory and analyze the temporal variation of the euglossine bees that occur in a neotropical hygrophilous forest. In order to sample male bees we used four chemical baits, eucalyptol, eugenol, vanillin, and methyl salicylate. The captures were made once a month, from March 2010 to February 2011, from 9:00 am to 12:00 pm. We captured 113 individuals of three genera and five species (in decreasing order of abundance): Eulaema nigrita Lepeletier, 1841 (n=52), Euglossa pleosticta Dressler, 1982 (34), Exaerete smaragdina (Guérin-Méneville, 1844) (12), Euglossa carolina Nemésio, 2009 (11), and Euglossa fimbriata Rebêlo & Moure, 1968 (4). The most attractive bait was eucalyptol (n=98), followed by vanillin (11), and eugenol (4). Both temperature and rainfall affected significantly the distribution of the number of males throughout the year. The highest number of Euglossini species and individuals was sampled in the warm and rainy season, with activity peaks varying among species.

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

“…When comparing the results of Euglossa fimbriata with those from other areas of SSF, the pattern found in the region of Palotina is somewhat different. This species is active throughout the year without evident seasonal variations in abundance in SSF areas in southeastern (Rebêlo & Garófalo, 1997;Castro et al, 2013;Knoll, 2016) and southern Brazil , not showing the marked seasonality in abundance that we present here.…”

“…Margatto, C. et al: Seasonality of orchid bees Pap. Avulsos Zool., 2019;v.59: e20195907 5/10 Suzuki, 2004;Castro et al, 2013;Knoll, 2016), and species presented a phenological pattern similar to that of sites elsewhere in the Atlantic domain (e.g., Rocha-Filho & Garófalo, 2014). As expected, only Ef.…”

“…With respect to phenology, the pattern found is the same, as the species presents a long period of activity during the year (Rebêlo & Garófalo, 1991Castro et al, 2013;Knoll, 2016) but with decrease in activity in the coldest/ dry period of the year (Rebêlo & Garófalo, 1997;Castro et al, 2013;Knoll, 2016). Moreover, a significantly seasonal pattern, with the highest abundance concentrated in early-middle summer was also registered by Castro et al (2013) and Knoll (2016). Interestingly, however, the species remains active during the entire year in areas with seasonal climates in lower latitudes (e.g., Andrade-Silva et al, 2012, but see Rocha-Filho & Garófalo, 2014.…”

“…Euglossa cordata occurs during the entire year, as observed in distinct areas along its distribution (e.g., Roubik & Ackerman 1987;Aguiar & Gaglianone, 2008;Rocha-Filho & Garófalo, 2014), including areas with distinct climate seasonality, as Caatinga (Andrade- Silva et al, 2012). But a seasonal peak on abundance distribution was not stated by Castro et al (2013) or Knoll (2016) in areas of SSF-Cerrado transition in southeastern Brazil. The pattern found here resembles the results found by Rocha-Filho & Garófalo (2014) in coastal areas of Atlantic forest, as the species remained active during the year but with a significant concentration in the wet season.…”

A database and synthesis of euglossine bee assemblages collected at fragrance baits

“…This dictates the level of analysis to the sampling site level rather than individual sampling events. Thus, with the current data, we can ask questions about variation in euglossine assemblages across sites, but it is hard to study, for example, seasonal variation in bee abundance or bait effects (see Ackerman 1983;Abrahamczyk et al 2012;Castro et al 2013). State-of-the-art methods such as the joint species distribution models used here can also be used to assess species associations, i.e.…”