PHORID FLIES (DIPTERA: PHORIDAE) OF LA SELVA

Phorids are small (1-6mm) flies found worldwide, but which are most diverse in the tropics. They are a diverse, but poorly known group, whose ways of life span scavenging, herbivory, parasitism and predation. A general reference about phorids is Disney (1994), who gives a key to genera and a discussion of all known life history information. All references given below are supplemental to those in Disney's book, or to research done specifically at La Selva. 

Acanthophorides spp.  

Several species are present at La Selva; all are associated with army ants. Females have parasitoid-type ovipositors, but the hosts are not known. 

Adenophora sp. 

There apparently are two species in this genus, which is widespread in the Neotropical Region. I collected the wingless females in nests of termites (Nasutitermes) in the Arboretum. 

Allochaeta sp. 

The way of life and specific identity of these flies has not yet been determined. Genus Apocephalus I have studied these flies in greater depth at La Selva than anywhere else in the New World. All are parasitoids, and most attack ants. Currently I am revising the group, so many undescribed species are given numbers only. 

Apocephalus antennatus Malloch  

These flies are parasitoids of fireflies (Coleoptera: Lampyridae). The species is widespread in the Nearctic and Neotropical Regions. References: Brown, 1993b, 1996. 

Apocephalus apivorus Brown  

Females of this species parasitize male stingless bees. Originally, I discovered this species at a stingless bee lek in the Arboretum. References: Brown, 1996, 1997-a. 

Apocephalus parallelus Brown 

Females of this and related species, belonging to the A. cultellatus- subgroup, are collected over army ant (Eciton burchelli) swarm raid fronts, but we don't know exactly what they are doing there. This species is known also from other lowland sites in Costa Rica, and from Peru. Reference: Brown, 1997-b. 

Apocephalus clavicauda Brown 

Species belonging to the A. cultellatus- subgroup, are collected over army ant (Eciton burchelli) swarm raid fronts, but we don't know exactly what they are doing there. This species is also in the A. cultellatus-subgroup, and probably occurs in similar situations, although it has so far only been collected in Malaise traps. It has also been collected near Braulio Carrillo National Park, and on the Osa Peninsula. Reference: Brown, 1997-b. 

Apocephalus completus Brown 

This is another species related to A. cultellatus which I have collected over Eciton burchelli army ants. It is also known from Peru. Reference: Brown, 1997-b. 

Apocephalus decurvus Brown 

We do not know anything about the life history of this unusual species, which is known only from a single female specimen. Reference: Brown, 1997-b. 

Apocephalus dichromatus Brown 

This is a common species at La Selva; probably it parasitizes attine ants. I have specimens from other lowland sites in Costa Rica as well. Reference: Brown, 1997-b. 

Apocephalus feeneri Disney 

This species was originally described from Texas, U.S.A., where it parasitizes ants of the species Pheidole dentata. 

Apocephalus laselvaensis Brown 

This species belongs to the A. infraspinosus- subgroup, and is also found near Bribri in Limon Province. The sister-species, A. occidentalis Brown, is found in western Costa Rica and Panama. Reference: Brown, 1997-b. 

Apocephalus lunatus Brown 

This is another relatively common species, whose hosts are unknown. Reference: Brown, 1997-b. 

Apocephalus parallelus Brown 

I collected females of this species, belonging to the A. cultellatus- subgroup, over army ant (Eciton burchelli) swarm raid fronts. This species is known also from other lowland sites in Costa Rica, and from Peru. Reference: Brown, 1997-b. 

Apocephalus paraponerae Borgmeier 

Females of this species seek out injured Paraponera clavata and oviposit in them. They are also attracted to other injured ants: Ectatomma tuberculatum, Pachycondyla vilosa and Pachycondyla apicalis. References: Brown and Feener, 1991a, b; Feener et al., 1996 

Apocephalus persecutor Borgmeier 

The hosts of this species are unknown. It is also known from Ecuador, where it was collected over army ants, and Brazil. 

Apocephalus praedator Borgmeier 

This species was collected originally over the army ant Labidus praedator in Panama. 

Apocephalus ritualis Brown 

A single female of this species was collected by Don Feener as a group of leaf-cutting ants, Atta cephalotes were tearing it apart. Presumably it parasitizes these ants. The females of related species land on the leaves carried by colony- bound workers and parasitize the ants through the mandibular suture. The ant colony responds by having hitchhikers, minor workers that patrol the column and attempt to repel these flies (sometimes they catch the fly, as in the specimen that Don grabbed). We have specimens also from near Guapiles and from Rio Palenque, Ecuador. Reference: Brown, 1997-b. 

Apocephalus securis Brown 

This is another A. cultellatus- subgroup species, found over army ant swarm raids. It is also found in Ecuador, Panama and Peru. Reference: Brown, 1997-b. 

Apocephalus singulus Brown 

This is another A. cultellatus- subgroup species, found over army ant swarm raids. It is also found in Ecuador. Reference: Brown, 1997-b. 

Apocephalus sinuosus Brown 

This is an unusual species whose way of life is unknown. It is also found in the Osa Peninsula. Reference: Brown, 1997-b. Apocephalus spinilatus Brown This species has also been collected in Colombia. Its way of life is unknown. Reference: Brown, 1997-b.

Apocephalus spinosus Brown

     This is a common species around Costa Rica. Recently, I saw females attacking Atta cephalotes at the Pitilla Biological Station in Guanacaste Province; presumably it attacks the same ant at La Selva. Reference: Brown, 1997-b.

Apocephalus tenuitarsus Brown

     This is a further species whose host is unknown. It is also known from Alajuela Province and from Colombia. Reference: Brown, 1997-b.

Apocephalus turgidus (Borgmeier)

     I recently synonymized the genus Pleurophorina with Apocephalus, which affected the name of this species. It is widely distributed in the New World tropics

Apocephalus vannus Brown

     This species has also been collected in Limon Province; its host is unknown. Reference: Brown, 1997-b.

Apocephalus spp.

     At least 66 other species of this genus are known from La Selva. I am in the process of revising a further group; names of those now identified by species numbers will be added when the revision is finished.

Apodicrania termitophila Borgmeier

     This is a common, widespread Neotropical species, whose way of life is unknown, but which has been collected elsewhere in association with termites.

Apterophora spp.

     There are two described females, but more described males of this group, which are often found associated with ants.

Beckerina spp.

     There are several species of this group at La Selva, but their way of life is completely unknown.

Borgmeieriphora multisetosa Brown

     This species was first recorded from my work at La Selva, but I later found specimens in Peru as well. The wingless females are found in the raids of the ant Eciton burchelli, but although they have a piercing, parasitic-type ovipositor, their hosts are unknown. The males fly above the ants, sometimes with the females in copula. Reference: Brown, 1993a.

Borgmeieriphora greigae Brown

     This species, known from a single female, was collected with a column of the army ant Eciton hamatum at La Selva. Reference: Brown, 1993a.

Calamiscus cryptopalpis Borgmeier

     Previously known only from females from Brazil, I recently reared adults of both sexes from injured stingless bees. Reference: Brown, 1997-c.

Chaetocnemistoptera semifurcata (Borgmeier)

     The way of life of these flies is unknown. 

Chonocephalus sp.

     There could be several species of this genus at La Selva. Females are wingless, and lay their eggs in decaying plant material. Some are also attracted to decaying insects.

Conicera sp.

     There are an unknown, small number of species of this genus that have been collected at La Selva. These are the well-known "coffin flies" that locate and oviposit on buried carrion.

Coniceromyia sp.

     They way of life of these flies is unknown. There are probably a few different species at La Selva.

Cootiphora angustata Brown

     This is another genus known only from the wingless females that also have a piercing, parasitic-type ovipositor. It was originally described from a single female in Ecuador.

Cremersia sp.

     There are probably several species of this genus at La Selva. All are parasitoids of army ants of the genera Labidus and Neivamyrmex.

Dacnophora sp.

     Like Cremersia, these flies are parasitoids of army ants of the genera Labidus and Neivamyrmex. There might be more than one species at La Selva.

Diocophora appretiata (Schmitz)

     These flies are always found in association with large army ant raids, but what they actually are doing is unknown. Other Diocophora species parasitize carpenter ants (Camponotus).

Dohrniphora spp.

     There are at least twenty species of this third largest phorid genus (after Megaselia and Apocephalus) at La Selva. Some are known to be scavengers.

Ecitophora collegiana Borgmeier, Ecitophora pilosula Borgmeier, 

Ecitophora varians Borgmeier and Ecituncula tarsalis Borgmeier.

     These four species are all widely distributed in the New World tropics, associated with army ants (Eciton spp.). The females are wingless or brachypterous, and the larvae of at least some species are scavengers in the nest. The development times of the larvae coincide with those of the ant brood (Rettenmeyer and Akre, 1968). At the end of army ant emigrations, which take place during the night, there are sometimes huge numbers of trail following flies and other army ant associates. 

Latiborophaga sp.

     There are two described Neotropical species in this genus, but one might just be the female of the other, which is known only from males. Their way of life is unknown.

Macrocerides abaristalis Borgmeier

     This species is also known from Ecuador, but in spite of its wide distribution, its life history is unknown.

Genus Megaselia

     This is by far the largest genus of phorids, its 1,500 described species making up about half of the family. Our understanding of the Neotropical fauna is fragmentary, and there are probably hundreds of undescribed species. At La Selva alone there could be one hundred or more species. Life histories for the group include scavenging, herbivory, predation and parasitism. Below I discuss a few species I have recognized from among the La Selva fauna.

Megaselia aurea (Aldrich)

     This species is a widespread scavenger, easily attracted to and reared from dead insects. There is an unusual behavior in this species, whose females form mating swarms rather than the usual male-dominated swarms (Sivinski, 1988).

Megaselia bella (Brues)

     I collected a number of females of this species on understory leaves over an army ant (Eciton burchelli) raid at La Selva. I do not know if the flies were associated with the ants.

Megaselia scalaris (Loew)

     This species is found nearly worldwide, probably spread by human activity. It develops in an incredible diversity of decaying organic materials, and might be a facultative parasitoid. Sometimes it invades wounded human tissues.

Melaloncha spp.

     These flies are parasitoids of bees. There are seven species that have been collected at La Selva.

Menozziola sp.

     Probably only one species of this genus has been collected at La Selva. They are parasitoids of queens of Camponotus ants.

Metopina sp.

     An unknown number of species of these small, scavenging flies are known from La Selva.

Myriophora sp.

     An unknown number of species of this genus are known from La Selva. They are parasitoids of millipedes, and can be attracted by crushing a prospective host.

Myrmomyia sp.

     Females of this genus are wingless; probably they are scavengers. Only one unidentified species has been collected at La Selva.

Myrmosicarius sp.

     These are parasitic species that attack Acromyrmex leaf-cutter ants. Their taxonomy needs revision, but probably only one or two species are present at La Selva.

Neodohrniphora calverti Malloch

     This species was collected by Malaise traps at La Selva. Hosts of related species are parasitoids of Acromyrmex leaf-cutter ants. 

Neodohrniphora curvinervis (Malloch)

     This species parasitizes the leaf-cutter ant Atta cephalotes, and has been the subject of some study. Females attack medium sized workers that are unladen (not carrying leaves); oviposition is through the occipital foramen. Because they are relatively large and conspicuous flies, females of this species are often incorrectly cited as the agent that causes "hitchhiking" in leaf-cutter ants. In fact, the hitchhikers defend against other parasitic phorids (Apocephalus spp.) that need to land on leaves carried by leaf-carrying, colony-bound workers. References: Feener and Brown, 1993; Orr, 1992.

Neodohrniphora sp.

     An undescribed species of this genus is present at La Selva. Its way of life is unknown.

Neopleurophora spp.

     The way of life of these flies is unknown. There are three species at La Selva.

Pachyneurella sp.

     This genus, if it is indeed a valid genus, has wingless females. The way of life is unknown, although they probably are scavengers. 

Phalacrotophora punctiapex Borgmeier

     The life history of this species was studied at La Selva. The larvae attack brood cells of sphecid wasps of the genus Trypoxylon, consuming the wasp egg and the spider provisions. References: Coville and Griswold, 1983, 1984.

Phalacrotophora spp.

     A few other species of this genus occur at La Selva. Most are probably parasitoids or kleptoparasites of solitary wasps and bees.

Phymatopterella sp.

     Nothing is known about the way of life of species of this genus. Two species are known from La Selva.

Physoptera pictiventris Borgmeier

     The way of life is unknown for all species of this genus. This species is also found in Brazil.

Pseudacteon browni Disney

     Females of this species can be seen commonly hovering over fire ants, Solenopsis geminata, in disturbed areas such as the lab clearing. The presence of these parasitoids significantly disrupts the ants foraging. Reference: Feener and Brown, 1992.

Pseudacteon spp.

     Several other species of these ant-parasitizing flies are known from La Selva.

Pseudohypocera kerteszi (Enderlein)

     This is a widespread Neotropical species that parasitizes bee nests. I have seen them coming and going from the nests of stingless bees in the Arboretum.

Puliciphora sp.

     Several species of this scavenging genus are found at La Selva. The females are wingless.

Rhyncophoromyia maculineura Borgmeier

     Females of this species parasitize the common carpenter ant Camponotus sericeiventris. It is found widely throughout the Neotropical Region. Reference: Brown and Feener, 1993.

Stichillus sp.

     There is one or two species of these flies at La Selva. Possibly they are parasitoids of bees, although convincing evidence is still lacking.

Styletta crocea Borgmeier

     Although this species clearly is a parasitoid, its host is unknown. It is found widely throughout the Neotropical Region.

Syneura sp.

     One species of this genus is known to be a parasitoid of scale insects. A single, unidentified species is known from La Selva.

Thalloptera schwarzmaieri Borgmeier

     The comments under Ecitophora apply equally to this species.

Trophithauma portentum Schmitz

     This is a widespread Neotropical species whose way of life is unknown.

Woodiphora sp.

     There could be several species of this genus at La Selva. Their way of life is unknown.

Literature cited

Brown, B.V. 1993a. Convergent adaptations in Phoridae (Diptera) living in the nests of social insects: a review of the New World Aenigmatiinae. In Danks, H.V. and G.E. Ball (editors). Systematics and entomology: diversity, distribution, adaptation and application. Memoirs of the Entomological Society of Canada 165:115-37.

Brown, B.V. 1993b. Taxonomy and preliminary phylogeny of the parasitic genus Apocephalus, subgenus Mesophora (Diptera: Phoridae). Systematic Entomology 18:191-230.

Brown, B.V. 1996. Preliminary analysis of a host shift: revision of the Neotropical species of Apocephalus, subgenus Mesophora (Diptera: Phoridae). Contributions in Science 462:1-36.

Brown, B.V. 1997-a. Parasitic phorid flies: a previously unrecognized cost to aggregation behavior of male stingless bees. Biotropica. 29: 370-372.

Brown, B.V. 1997-b. Revision of the Apocephalus attophilus -group of ant-decapitating flies (Diptera: Phoridae). Contributions in Science. 468: 1-60.

Brown, B.V. 1997-c. Systematics and fossil evidence of host-parasitoid relationships of Calamiscus Borgmeier (Diptera: Phoridae). Journal of Natural History. 31: 1253-1259.

Brown, B.V. and D.H. Feener Jr. 1991a. Behavior and host location cues of Apocephalus paraponerae (Diptera: Phoridae), a parasitoid of the giant tropical ant Paraponera clavata (Hymenoptera: Formicidae). Biotropica 23:182-87.

Brown, B.V. and D.H. Feener Jr. 1991b. Life history parameters and immature stages of Apocephalus paraponerae (Diptera: Phoridae), a parasitoid of the giant tropical ant Paraponera clavata (Hymenoptera: Formicidae). Journal of Natural History 25:221-31.

Brown, B.V. and D.H. Feener Jr. 1993. Life history and immature stages of Rhyncophoromyia maculineura, an ant-parasitizing phorid fly (Diptera: Phoridae) from Peru. Journal of Natural History 27:429-34. 

Coville, R.E. and C. Griswold. 1983. Nesting biology of Tripoxylon xanthandrum in Costa Rica with observations on its spider prey (Hymenoptera: Sphecidae; Araneae: Senoculidae). Journal of the Kansas Entomological Society 56:205-16. 

Coville, R.E. and C. Griswold. 1984. Biology of Trypoxylon (Trypargilum) superbum (Hymenoptera: Sphecidae), a spider-hunting wasp with extended guarding of the brood by males. Journal of the Kansas Entomological Society 57:365-76. 

Disney, R.H.L. 1994. Scuttle flies: the Phoridae. London: Chapman and Hall, xii + 467 pp. 

Feener, D.H., Jr. and B.V. Brown. 1992. Reduced foraging of Solenopsis geminata (Hymenoptera: Formicidae), in the presence of parasitic Pseudacteon spp. (Diptera: Phoridae). Annals of the Entomological Society of America 85:80-84. 

Feener, D.H., Jr. and B.V. Brown. 1993. Oviposition behavior of an ant-decapitating fly, Neodohrniphora curvinervis (Diptera: Phoridae) and defense behavior by its leaf-cutting ant host, Atta cephalotes (Hymenoptera: Formicidae). Journal of Insect Behavior 6:675-88. 

Feener, D.H., Jr., L.F. Jacobs, and J.O. Schmidt. 1996. Specialized parasitoid attracted to a pheromone of ants. Animal Behavior 51:61-66. 

Orr, M.R. 1992. Parasitic flies (Diptera: Phoridae) influence foraging rhythms and caste division of labor in the leaf- cutter ant, Atta cephalotes (Hymenoptera: Formicidae). Behavioral Ecology and Sociobiology 30:395-402. 

Rettenmeyer, C.W. and R.D. Akre. 1968. Ectosymbiosis between phorid flies and army ants. Annals of the Entomological Society of America 61:1317-26. 

Sivinski, J. 1988. Unusual female-aggregated mating systems in phorid flies. Journal of Insect Behavior 1:123-28.