Notes on the occurrence of the Iberian endemic Dasylabris egregia (Klug, 1835) (Hymenoptera, Mutillidae, Dasylabrinae) in Portugal

Mutillid wasps (Mutillidae; also known as velvet ants) are ectoparasitoid Hymenoptera with more than 4600 species known worldwide, of which at least 150 occur in Europe (e.g. ‍Lelej, 2002; ‍Pagliano et al., 2020); within this family, species are characterized by extreme sexual dimorphism (generally males are winged and females wingless), with both sexes frequently exhibiting very different chromatic patterns; in consequence, unless both sexes are found in copula, sex-associations are difficult to establish and each sex is frequently described independently as a different species.

The Mutillid wasp fauna of Spain has been studied in some detail during the 20^th century; elaborated over an unfinished manuscript by the entomologist Ricardo García Mercet, the work by José Giner Marí (‍1944) was an attempt to summarize the knowledge to that date, and from the 1950’s Francisco J. Suárez published what are still the most relevant works regarding Iberian Mutillid wasps to the present day (e.g. ‍Suárez, 1952, ‍1954a, ‍b, ‍1959, ‍1988, among others). By contrast, the respective fauna of Portugal has received little attention, and despite occasional mentions to Mutillid wasps in general faunistic works (e.g. ‍Diniz, 1959, ‍1989, and more recently ‍Baldock et al., 2020), the present country-level knowledge about this family is extremely incomplete, with gaps that will take considerable effort to mitigate.

The genus Dasylabris Radoszkowski, 1885 (Dasylabrinae) is currently considered to be composed of five species within the Iberian Peninsula, four of those in the subgenus Dasylabris s.s.: D. atrata (Linnaeus, 1767), D. egregia (‍Klug, 1835), D. iberica Giner, 1942 and D. maura (Linnaeus, 1758), and one in the subgenus Inbaltilla Lelej, 1976: D. lugubris (‍Klug, 1835); e.g. Giner Marí (‍1944), Lelej (‍2002).

Dasylabris egregia was originally described from the male sex, collected in Puerto Real (Andalusia, Spain; ‍Klug, 1835; ‍Lelej, 2002); the female sex was described separately by André (‍1903), as Mutilla maura var. calonota, based on a specimen from Madrid; the correct male-female sex association was first suggested by García Mercet (‍1903), then by Junco y Reyes (‍1941) and finally formalized by Giner Marí (‍1944) by inference (i.e. no pair in copula was obtained), synonymizing André’s taxon. Records of this species are relatively scarce and known from the southern half of Spain, from Madrid to Andalusia and particularly from the south-eastern provinces (Fig. 1; Appendix 1); the species was thought to be endemic of Spain until two records were recently reported by Baldock et al. (2020). Partially in consequence of its scarcity nothing is known about its potential host species or other aspects of its ecology.

In July 2019, while making a direct effort to collect Mutillid wasps, the author found a female D. egregia running over the dunes north of Vila Nova de Milfontes (Odemira, Beja, Portugal).

Material: 1♀, Vila Nova de Milfontes (Odemira, Beja, Portugal), 37º45’18.04’’N, 8º47’56.70’’W, alt. 51 m a.s.l., 18.vii.2019, 11:10 GMT (R. Matias, det., leg. & coll.); Figs. 2-‍3.

The specimen (length: 14.2 mm) lacks the last antennomere of the right antenna and, attached to the right femur 2, there is a parasite (undetermined Acari). Morphologically, it is identical in every respect to typical Spanish specimens.

The two other records recently published from coastal Portugal (‍Baldock et al., 2020), both localities north of the record here described, are: 1♀, Carvalhal (Grândola, Setúbal), 22.vii.2016, det. Romano, leg. J. Halada, coll. Romano; 1♀, Santo André (Santiago do Cacém, Setúbal), 5.viii.2018, det. Baldock, leg. M. & E. Howe.

Dasylabris egregia is therefore an Iberian endemic, but evidently rare in Portugal, where it currently is known only from three coastal locations (Fig. 1), all in Alentejo, associated with extensive sand dunes. In Spain it occurs not only in this type of habitat but also in well preserved cork oak forests and other dry and non-coastal areas (e.g. Los Alcornocales Natural Park, Cádiz; Appendix 1), including montane habitat and Mediterranean scrubland (e.g. in the provinces of Granada and Malaga; Appendix 1); this fact extends considerably the potential area of occurrence in Portugal, which may be less fragmented than the three currently known records could suggest. Sand dunes are continuous in a strip along the south-western coast from Tróia to Sines (where the 2016 and 2018 specimens were found), with further large expanses of coastal sand dunes South of Sines at Almograve, Vila Nova de Milfontes (the locality of the present record), around Aljezur (Amoreira) and at Carrapateira; on the other hand, formerly favourable habitat along the coast of Algarve (southernmost Portuguese province) is now probably too degraded and anthropized to hold populations of the species, but the Ria Formosa Natural Park (in particular at the barrier islands) might be the best area to search for the species presently. Habitat changes and habitat loss are two of the most important threats to thepresence of D. egregia in the region; large areas of biodiverse habitats are currently under intense human pressure, even within nationally protected areas (e.g. “Parque Natural do Sudoeste Alentejano e Costa Vicentina”), where they are being converted to intensive agriculture and to build tourism-related infrastructures, such as golf courses and large touristic resorts at the expenses of the destruction of natural habitats.

These records significantly increase the previously known distribution of the species; they indicate most probably it has remained undetected in those areas, rather than a recent expansion. This fact is relevant, as it is an indication of the poor sampling effort made in Portugal regarding Mutillid wasps (with obvious consequences to the knowledge of this group), given that D. egregia is a very large, striking and easily identifiable species (particularly the female), despite being a scarce species. It further suggests an inadequately known biodiversity in large areas of the Portuguese territory, which is a limitation to measure potential biodiversity loss.

In conclusion, further continuous effort is necessary to conveniently describe not only the distribution and real abundance of this species but also of the remainder Portuguese Mutillid wasps fauna.