NeotropicalCopestylum(Diptera, Syrphidae) breeding in Agavaceae and Cactaceae including seven new species

Abstract

We studied 42 species of saprophagous, Neotropical Copestylum (Diptera, Syrphidae) reared from decaying Cactaceae and Agavaceae. Thirty-three species were reared during fieldwork in Bolivia, Costa Rica, Ecuador, Mexico, Peru, and Trinidad from 1998-2007. Nine species came from museum and private collections. Seven were new species. We describe these new species and the third stage larva and/or puparium and breeding sites of 40 species. Not described are two apparent species related to Copestylum apicale (Loew, 1866) reared from Cactaceae. Resolution of their status was beyond the scope of this paper but reference is made to their distinctive larval morphology. Based on early stage characters all reared species can be placed in ten species groups, all but three of which have been recognized previously on the basis of adult characters. A high level of congruence was found between adult and larval characters in terms of these species groups. Eight of the groups appear to be related closely and may represent a monophyletic lineage within Copestylum that has diversified in xeric habitats. Early stage morphology varied within and amongst groups but two trends in functional morphology are recognizable. One trend is towards feeding in watery decay and the other towards feeding in firmer decay. The latter trend is characterized by species that scoop food and use grinding mills in their head skeletons to break it up. They also have armoured thoraces with varying arrangements of sclerotized spicules or stiffened setae for gripping and protection during tunnelling, a short anal segment, and a short posterior breathing tube for protecting the openings. The former trend is characterized by species with opposite and contrasting features. They filter food and have well-developed pre-oral setal filters but they lack grinding mills or only have poorly developed grinding mills. They have reduced thoracic armature, elongate anal segments, and posterior breathing tubes which facilitates simultaneous feeding and respiration. Comparison with 23 Copestylum species reared from bromeliads (Bromeliaceae) suggests a common pattern of diversification in that species groups with the largest body sizes are more specialized.

Temporal shifts and niche overlapping in Copestylum (Diptera, Syrphidae) communities reared in cactus species in a central Mexican scrubland

“…In this sense, C. truncatum and C. limbipenne exhibit similar trophic and biological features (Rotheray et al 2009), and they share an ecological niche and tend to split seasonally: C. truncatum is abundant in the dry season, and while C. limbipenne is abundant in the wet season.…”

“…C. latum scoop food to break tissues up whereas C. mila filter food and only feed on watery tissues (Rotheray et al 2009). So they may feed on different segments of the rotten stems of cacti or they facilitate each other in the assemblage.…”

A critical role for Copestylum larvae (Diptera, Syrphidae) in the decomposition of cactus forests

“…The primary insects found in decaying stems of cacti in central Mexican scrublands are Copestylum larvae (Diptera, Syrphidae) Pérez-Bañón, 2001, 2002;Martínez-Falcón et al, 2008;Rotheray et al, 2009;Martínez-Falcón et al, 2011). However quantified estimates of their role in decomposition processes have not been made (Martínez-Falcón et al, 2010, 2011.…”

Las relaciones secretas entre cactus, sírfidos y bacterias contribuyen al mantenimiento del ecosistema semiárido mexicano

“…En ese mismo trabajo se demuestra un mayor solapamiento de nicho en la época de secas que en la época de lluvias, sugiriendo estos resultados que de acuerdo a la estacionalidad, las especies se reparten los recursos de forma diferente. Otro hallazgo derivado de los muestreos realizados en el territorio de esta Reserva de la Biosfera, fue el descubrimiento de una nueva especie para la ciencia, Copestylum hidalgense Marcos-García & Rotheray, 2009, endémica de la zona y cuyo nombre fue dedicada a Hidalgo, el estado de México donde fue descubierta (Rotheray et al 2009). …”