Biological notes on a fungus-growing ant, Trachymyrmex cf. zeteki (Hymenoptera, Formicidae, Attini) attacked by a diverse community of parasitoid wasps (Hymenoptera, Diapriidae)

Abstract

A number of wasps in the family Diapriidae, subfamily Diapriinae (Proctotrupoidea), are parasitoids that specialize on ant larvae. These wasps are abundant and diverse in the Neotropics, but little is known about their biology. We studied parasitism rates by an array of diapriine wasps that attack the larvae of fungus-growing ants, Trachymyrmex cf. zeteki, in a single population (near Gamboa, Panamá). Relatively little is known about the biology and natural history of these ants, so we also present data on colony size and nest architecture. We excavated 136 colonies in central Panamá We reared six wasp morphotypes; two of them in the genus Mimopriella Masner and Garcia, one Oxypria Kieffer, two Szelenyiopria Fabritius and one Acanthopria Ashmead. The mean intensity of larval parasitism per ant colony was 33. 9% (2006), and its prevalence across all ant populations was 27. 2% (2006 and 2009). Parasitism rates were not positively correlated with host colony size. A single case of super-parasitism was documented in which two Oxypria males were reared from the same host larva.

An Evaluation of the Possible Adaptive Function of Fungal Brood Covering by Attine Ants

“…Mycelial cover may act as a physical barrier against tiny parasitoid wasps. Observations that larvae of species from several attine genera with extensive mycelial covers are heavily parasitized by diapriinae wasps (Loiácono et al 2000;Fernández-Marín et al 2006a;Pérez-Ortega et al 2010) neither support nor refute this idea because we do not know if parasitism would be higher without the mycelial cover. These parasitoids are little studied, but they are relatively diverse and abundant in both Trachymyrmex and Cyphomyrmex, which have a low and high extent of fungal brood covering, respectively.…”

“…Genera Eggs Larvae Pupae but the mycelial cover adheres directly to the cuticular surface instead of having an airspace in between, as is found between a pupa and its silk cocoon. The function of this behavior is not resolved, although three untested hypotheses have been proposed: (1) protection against predators such as army ants or parasitism by wasps (LaPolla et al 2002;Powell and Clark 2004;Fernández-Marín et al 2006a;Pérez-Ortega et al 2010); (2) protection against potentially adverse environmental factors (Mueller et al 2010); and (3) protection from microbial parasites (Lopes et al 2005;Mueller et al 2010). We focus our analyses on the third hypothesis, because there is ample evidence that the advent of attine fungus farming around 50 million years ago (Schultz and Brady 2008) has confronted these ants with multiple challenges from parasites that are absent in many other ants.…”

Diapriinae Wasps (Hymenoptera: Diaprioidea: Diapriidae) Associated with Ants (Hymenoptera: Formicidae) in Argentina

“…Fernández-Marin et al [9] found that between 27% and 70% of the colonies of two species of Cyphomyrmex Mayr were parasitized by one species in Puerto Rico and by up to four concurrent morphospecies of diapriids in Panama. Similarly, Pérez-Ortega et al [7] reported that another fungus-growing ant, Trachymyrmex cf. zeteki, was attacked by a diverse community of diapriids in Panama, with a mean intensity of larval parasitism per ant colony of 33.9%, and prevalence across all ant populations of 27.2%.…”

“…As true for the most social insects, they accumulate significant stores of resources within their nests, attracting a diverse array of predators, microbial pathogens, and parasites [7]. We studied aspects of the intensity and prevalence of these littleknown diapriine wasps that attack the larvae of the fungusgrowing ant, Acromyrmex lobicornis Emery, and noted a remarkably diverse community of parasitoids within host population from four localities of La Pampa, Argentina [4,8].…”

“…Luis De Santis (1914Santis ( -2000 catalogued associations between diapriids and ants [16,17] and reported new geographic distributions [18]. Marta Loiácono and colleagues studied Neotropical myrmecophiles diapriids and their interactions with ants [4,7,8,15,[19][20][21][22][23][24][25][26][27][28][29].…”