Dilophus bicoloripes Edwards, 1938

Pacheco Da Silva, Vitor C., Schelesky-Prado, Daniel De C., Fitzgerald, Scott J., Serra, Wilson Sebastián, Scarabino, Fabrizio, Costa, Andrés, Hagopián, Damián & Martínez, María, 2025, Bibionidae (Diptera: Bibionomorpha) from Uruguay: updated inventory including first reports of four species, Zootaxa 5588 (1), pp. 129-146 : 142-143

Dilophus bicoloripes Edwards, 1938

Distribution. Argentina, Brazil.

Dilophus bicoloripes Edwards ( Fig. 6D ) was recorded on Ilha Brasileira (iNaturalist), an island in the border between Brazil and Uruguay that has been claimed by both Brazil and Uruguay, but has been administered by the Brazilian government. For this reason it has not been included in our study although it must be present in the north of Uruguay.

Several other entomological collections (particularly in Argentine museums) or recent collections may contain unpublished records of Bibionidae from Uruguay. The examination of these collections as well as verifying the identity of some specimens in European museums mentioned in this work will be priorities to be developed in the future.

Larvae of Bibio and Dilophus deposited in the Entomological collection of Facultad de Ciencias originate from the stomach content of wild boars Sus scrofa (Linnaeus, 1758) ( Suidae ) ( Lombardi et al 2015). Samples preserved in 70% alcohol, each in a 1 liter container, were obtained from three wild boars collected in 2006, two were captured in the department of Colonia and the third in Maldonado. In the samples of the stomach contents of wild boars, vegetables, seeds, and remains of arthropods were found, being the most abundant the bibionid larvae. It is possible that the larvae analyzed here were consumed by wild boars because they were in decomposed plant material that was used as food, once, Bibionidae larvae feed gregariously in organic matter, rotten plant material and among roots ( Carvalho et al. 2012), where wild boars may feed. However, since both adults and larvae of bibionids are an important food source for some vertebrates, such as temperate region birds ( Fitzgerald 2009), and larvae have also been found in the diet of the Afrotropical mammal Armored shrew, Scutisorex somereni (Thomas) ( Skartveit 2017) , it is quite likely that the ingestion of the larvae by the wild boars was not circumstantial. However, it remains unknown what nutritional value this type of food has for wild boars and if bibionid larvae are a common component of the wild boar’s diet, either in its native environment or into which it has been introduced. This is the first record of animals feeding on Bibionidae larvae in the Neotropical region. Another important observation is that in both Entomological Collections Bibio samples are scarce, however, the number of larvae observed in the stomach contents of wild boars shows that they are not rare. This leads us to believe that for some unknown reason there are failures in the collection of adult Bibio flies or that they have a high mortality rate in the larval/pupal stage and are therefore rarely collected. Another possible explanation is that this species of Bibio is seasonal or has peaks in occurrence and the collections were carried out outside the period in which they occur in large numbers, similar to that reported for some European species ( Skartveit 1995)

Seven species from three genera are recorded in the country, namely: Bibio Geoffroy , with the species Bibio dacunhai Hardy , Dilophus Meigen with three species, Dilophus collaris Guérin-Méneville , Dilophus pectoralis Wiedemann and Dilophus aff. tetracanthus Edwards , and Plecia Wiedemann , with three species, Plecia collaris (Fabricius) , Plecia gibbosa Hardy and Plecia ramosa Fitzgerald. Bibio dacunhai , P. collaris , P. gibbosa and P. ramosa as well as the genera Bibio and Plecia , are recorded for the first time in Uruguay.

Figures

FIGURE 6. INaturalist photos of Bibionidae from Uruguay in life. A B Dilophus pectoralis Wiedemann ♀, C Dilophus sp. ♂♀, D Dilophus bicoloripes Edwards ♀, E Plecia aff. gibbosa ♀, F Plecia sp. ♀♂, G Dilophus pectoralis Wiedemann ♀ under predation by Cosmoclopius nigroannulatus Stål. Photos by: Andrés Costa (A, B, G), Joaquín Davila (@joaco5 from Inaturalist) (C), Fernando Sessegolo (@fmiudo from Inaturalist (D), Luis Vescia da Rosa (@luisvescia from iNaturalist) (E), Guillermo Menéndez (@gmmv80 from Inaturalist) (F).