The phenology of a Neotropical ant assemblage: evidence for continuous and overlapping reproduction

Abstract

Reproductive phenologies reflect the interaction between the mating system of a taxon and the local environment. Ant colonies reproduce and disperse via the flights of winged alates. Few data exist on the reproductive phenologies of ant assemblages. Here we analyze the reproductive phenologies of 81 common ant species from 23,182 individuals collected over 3 years on Barro Colorado Island, Panama (BCI). Species ranged from highly synchronous to continuous fliers, but showed a median flight duration of at least 8 of 13 lunar months. In two statistical analyses (variance ratio test and Spearman rank correlations), 84% (16 of 19) of ant genera had species trending toward positively associated phenologies, more than expected by chance (P<0.00036 by a binomial test). Thus, there was little evidence for the hypothesis that competition for limiting resources staggers congeneric flights and ultimately promotes reproductive isolation. On the contrary, the timing of reproduction, and its synchrony, tended to be conserved within genera and subfamilies. These results closely match phenological studies of plant assemblages. The continuous reproduction and small colony size of many species in this study suggest that the female calling syndrome, a poorly documented mating system in ants, may be common on BCI. (Whitford 1978;Lynch et al. 1980;Cerda et al. 1997;Kaspari and Weiser 2000). Far less is known, however, about the phenology of ant reproduction and dispersal (Tschinkel 1991) even though this knowledge is key to understanding patterns of genetic and species diversity. It is an especially intriguing topic for tropical assemblages where over 100 species may be found in 100 m 2 of forest (M. Kaspari and J.T. Longino, personal observation). KeywordsHere we present the first data set documenting patterns and possible mechanisms generating phenological diversity in a tropical ant assemblage. We begin by briefly exploring the major constraints to the reproductive phenology of an ant population. We then discuss how taxonomic diversity in phenologies may arise.What determines the reproductive phenology of an ant population?Reproductive and dispersal phenologies are compromises to a variety of biotic and abiotic constraints (Rathcke and Lacey 1985). In ants, a key element of this constraint is the dual nature of the flights themselves: alates must not only find a mate, but females must then go on to found a colony.Ants show at least two mating systems that involve alates (Hölldobler and Bartz 1985). Both have a pheno-

Phenology of mating flight in Ecitoninae (Hymenoptera: Formicidae) in a Brazilian Atlantic Forest location

“…Flight segregation has also been suggested for other species of ants of temperate regions (Noordijk et al 2008), as well as North American Ecitoninae (Baldridge et al 1980;Hölldobler & Wilson 1990) and African Dorylinae (Haddow et al 1966). However, this is not evident in most of species assemblies of tropical regions (Kaspari et al 2001b). …”

“…Reproductive phenologies often refl ect species adaptations to their abiotic and biotic environments (Rathcke & Lacey 1985;Kaspari et al 2001b;Frederickson 2006). In temperate regions, ant mating fl ights are restricted to a single day, a few days, or a few weeks per year, occurring sometimes during spring, but principally in summer, such as in Lasius spp.…”

A taxonomic revision of the Meranoplus F. Smith of Madagascar (Hymenoptera: Formicidae: Myrmicinae) with keys to species and diagnosis of the males

“…None of these descriptions provide diagnosis of Meranoplus males for any biogeographic region or locale, and most do not provide sufficient detail for genuslevel identification. Given the potential of male ants to clarify the natural history of ant reproductive biology (Kaspari et al 2001), improve the discovery and definition of genera (Yoshimura & Fisher 2009, 2011, 2012a, and aid ant taxonomy and systematics (Brady & Ward 2005;LaPolla 2004;Song & Bucheli 2010;Yoshimura & Fisher 2012b), including descriptions of male ants is a research priority.…”

How ants find each other; temporal and spatial patterns in nuptial flights

“…Reproduction behaviour and phenology are key factors for any species and need to be recognized to under-A C H T U N G T R E N N U N G stand species occurrence and population characteristics (TschinA C H T U N G T R E N N U N G kel, 1991; Kaspari et al, 2001a). For ants, with a relative sessile way of living, flight capable sexuals are of high importance to ensure outbreeding, the founding of new colonies and the colonization of new areas (Kannowski, 1963;Hçlldobler and Wilson, 1990;Mabelis, 1994).…”