EUROPEAN JOURNAL OF ENTOMOLOGY

Eur. J. Entomol. 103 (2): 347-353, 2006 | DOI: 10.14411/eje.2006.045

Life-history variation in three coexisting species of carnid flies (Diptera: Carnidae), Carnus hemapterus, Hemeromyia anthracina and Hemeromyia longirostris

Francisco VALERA¹, Manuel MARTÍN-VIVALDI², Miguel CARLES-TOLRÁ³

¹ Estación Experimental de Zonas Áridas (Consejo Superior de Investigaciones Científicas), General Segura 1, E-04001 Almería, Spain; e-mail: pvalera@eeza.csic.es

² Departamento de Biología Animal y Ecología, Facultad de Ciencias, Universidad de Granada, Campus de Fuentenueva s/n, 18071 Granada, Spain

³ Avda. Príncipe de Asturias 30, ático 1; E-08012 Barcelona, Spain

Seasonal cycles constitute a major challenge for organisms since they may influence the genetic composition of a population, the species structure of a community and the interactions between organisms. Diapause is frequently used by insects to synchronize their life cycle with seasonal changes and is regarded as a key factor in the coexistence of competing species. Here the occurrence, abundance and emergence patterns of three poorly-known species of carnid flies (Carnus hemapterus Nitzsch, 1818, Hemeromyia anthracina Collin, 1949 and Hemeromyia longirostris Carles-Tolrá, 1992), which overwintered in the nests of several bird species at two localities, are reported and evidence of possible interspecific competition sought. Larvae of all three species were found in association with carrion and detritus. Both Hemeromyia species co-occurred in around 50% of the nests and Carnus with each of the Hemeromyia species at a lower rate (30-40% of the nests). Coexistence of all three carnid species was rare. We did not find any evidence of interspecific competition in the larval stage. Coexistence did not reduce the number of flies that emerged of any of the three species and the abundance of some species was even positively related. Species-specific emergence patterns and different habitat selection criteria (Carnus hemapterus seemed to avoid nests lined with vegetable material), which diminished the overlap between species were found. Such spatial and temporal segregation could facilitate the coexistence of these closely related species, which have similar ecological requirements, and might influence the seasonal dynamics of this poorly-known assemblage of insects inhabiting the nests of birds.

Keywords: Diptera, Carnidae, Carnus hemapterus, coexistence, diapause, emergence, Hemeromyia, seasonal cycles, temporal and spatial segregation

Received: July 1, 2005; Revised: October 10, 2005; Accepted: October 10, 2005; Published: April 6, 2006  Show citation