Biodiversity Data Journal :
Research Article
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Corresponding author: Emily A. Hartop (ehartop@nhm.org)
Academic editor: Vladimir Blagoderov
Received: 21 Nov 2016 | Accepted: 25 Jan 2017 | Published: 31 Jan 2017
© 2017 Brian Brown, John Hash, Emily Hartop, Wendy Porras, Dalton Amorim
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Brown B, Hash J, Hartop E, Porras W, Amorim D (2017) Baby Killers: Documentation and Evolution of Scuttle Fly (Diptera: Phoridae) Parasitism of Ant (Hymenoptera: Formicidae) Brood. Biodiversity Data Journal 5: e11277. https://doi.org/10.3897/BDJ.5.e11277
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Numerous well-documented associations occur among species of scuttle flies (Diptera: Phoridae) and ants (Hymenoptera: Formicidae), but examples of brood parasitism are rare and the mechanisms of parasitism often remain unsubstantiated.
We present two video-documented examples of ant brood (larvae and pupae) parasitism by scuttle flies. In footage from Estação Biológica de Boracéia in Brazil, adult females of Ceratoconus setipennis Borgmeier can be seen attacking workers of Linepithema humile (Mayr) species group while they are carrying brood, and ovipositing directly onto brood in the nest. In another remarkable example, footage from the Soltis Center, near Peñas Blancas in Costa Rica, shows adult females of an unidentified species of the Apocephalus grandipalpus Borgmeier group mounting Pheidole Westwood brood upside-down and ovipositing while the brood are being transported by workers. Analysis of evolutionary relationships (in preparation) among Apocephalus Coquillett species shows that this is a newly derived behavior within the genus, as the A. grandipalpus group arises within a group of adult ant parasitoids. In contrast, relationships of Ceratoconus Borgmeier have not been studied, and the lifestyles of the other species in the genus are largely unknown.
tropical, parasitoids, rain forest, biodiversity
The Phoridae (Insecta: Diptera) are a large group of small flies that are found worldwide. The ways of life of the majority of species are completely unknown, although they are frequently referred to as scavengers, based on the lifestyles of the best-known species. Enough fragmentary knowledge exists, however, to refer to phorids as one of the most biologically diverse groups of insects, with various species being scavengers, herbivores, fungivores, predators, parasitoids, and true parasites (compiled by
As parasitoids (insects that feed on or in a single host for their development, eventually killing it), phorids have evolved to exploit a wide variety of hosts, but especially well-known is their use of ants (Formicidae), bees (mostly Apidae), millipedes (Diplopoda), and termites (Isoptera). Both commensal and parasitoid relationships with these other insects are common (with the exception of millipedes), but usually the parasitoids are confined to attacking adults of their hosts, as documented in copious field observations (e.g.,
In this paper we provide video documentation of startling newly observed behaviors in two species of phorid flies, showing that they are aggressive and unequivocal parasitoids of immature ants.
In Brazil, ant nests were located by cutting open rotting logs in early November 2016. The exposed colonies were then observed to record phorid fly attack. Footage at the Estação Biológica de Boracéia was obtained with both an Olympus OMD-EM1 outfitted with a 60 mm Olympus macro lens (Figs
In Costa Rica, Pheidole sp. nests were collected under the leaves of a Chamaedorea palm (Fig.
Ants were identified by A. Wild. Phorids were identified by B. Brown, E. Hartop, and J. Hash. W. Porras and D. Amorim contributed to fieldwork.
Nests of the ant Linepithema sp were common in decaying logs in clearings and roadsides near the Boracéia station. Exposure of the colony quickly attracted both an aerial phorid parasitoid (Pseudacteon sp.) and individuals of Ceratoconus setipennis (Figs
The five known species of Ceratoconus are described only from Brazil (
In our Costa Rican example, Pheidole nests were generally restricted to single leaflets, often covering half or more of the under surface. In approximately half an hour of searching, 8-9 of these Pheidole nests were found. While dissecting nests on plastic sheets in the field, in search of Pheidolomyia Schmitz (Phoridae) females, large numbers of Apocephalus females arrived at the dissected nests. Female Apocephalus grandipalpus group females were observed running on the substrate and hovering above ants. Flies only briefly hovered above ants that were not carrying brood before moving back to the leaf substrate or assessing another ant (Fig.
The discovery of ant-brood parasitism in these two phorids demonstrates that this behavior has evolved at least twice in the family. The genus Apocephalus was proposed to be monophyletic by
The relationships among Ceratoconus species, and of this genus to other phorid genera have not been studied. Some species are known, however, to be associated with army ants (Formicidae: Ecitoninae). These associations might be fortuitious, however, as army ant raids commonly induce colonies of ants to evacuate their nests, allowing phorid parasitoids access to the fleeing colony (
The video documentation of two very different types of brood parasitism of ant species by scuttle flies was recorded in two countries within just a few months of one another. This hints at the many remarkable behaviors of phorid flies that may still await discovery by the patient observer. It appears brood parasitism may not be as rare as was once assumed, and that there may be a tremendous amount of information to uncover about these behaviors.
We thank Lisa Gonzalez, Gabi Pirani, and Heloísa Fernandes Flores for their hard work and good company while in the field in Brazil. Carlos Lamas is thanked for his assistance at the Museu de Zoologia da Universidade de São Paulo. Keith Bayless and Olivia Evangelista are thanked for their help and hospitality in São Paulo. Carol Bornstein is thanked for her plant identification, Alex Wild is thanked for his ant identification. Field work in Costa Rica was supported by National Geographic Grant number 9654-15 to J. Heraty and J. Hash. Field work in Brazil was supported by R. Lavenberg and the Natural History Museum of Los Angeles County. Further funding was also received from E. Chao, C. and M. Conlan, and G. and M. Wallace.