Nemausus sordidatus (Stal, 1858)

Davranoglou, Leonidas-Romanos, Cheiladakis, Nikos & Makris, Christodoulos, 2021, First record of the broad-headed bug Nemausus sordidatus (Stål, 1858) (Hemiptera: Heteroptera: Alydidae) from Greece and Cyprus, Israel Journal of Entomology 51, pp. 1-6 : 2-5

Nemausus sordidatus

can be readily distinguished from all other European species in the family Alydidae by the following combination of characters: body orange to light brown, distal portion of hind femur and base of hind tibia darkened; macropterous; fourth antennal segment slightly shorter than segments two and three combined; second labial segment longer than third and fourth combined; hind femur not enlarged; ventral surface of hind tibia armed distally with five spines; first tarsal segment 1 to 1.5 times as long as remaining tarsal segments combined.

These characters have been observed in both specimens and confirm the identity of the species ( Figs 1, 2).

We presume that N. sordidatus is almost certainly an invasive species in all parts of its European distribution, for the following reasons:

(1) All life instars of N. sordidatus depend on Acacia species, which are not native to any part of Europe. The specimen from Crete was found in Chania, where several plantations of the highly invasive A. saligna occur (Cheiladakis, pers. obs.), which is also the host plant for N. sordidatus in Sicily ( Carapezza et al. 2020).

(2) All specimens were found in heavily disturbed, anthropogenic environments; the specimens from Crete and Cyprus were photographed in the central areas of the cities of Chania and Lemesos, respectively.

(3) Most European records have been made over the last 16 years ( Carapezza et al. 2020; Vivas & Burgers 2015), with the exception of CÁdiz and MÁlaga, Spain ( Ribes 1971; VÁzQuez 1985). It is unlikely that a fairly large, non‐cryptic and actively dispersing insect such as N. sordidatus would have evaded areas where several heteropterists have been collecting for years (e.g. Crete, Cyprus, Sicily).

It is likely that at least in Crete, this species has been introduced by humans and not due to active or passive aerial dispersal, as this island is very far from areas where this species was previously recorded. The situation in Cyprus, Sicily, Spain and Portugal is less clear. Only molecular analysis of different populations of N. sordidatus will elucidate the origin of this species in Europe and its invasion dynamics.

Since N. sordidatus appears to feed exclusively on introduced Acacia spp. ( Carapezza et al. 2020; Vivas & Burgers 2015), its presence in Europe is unlikely to be of economic importance. On the other hand, N. sordidatus is known to form occasionally large populations in patches of Prosopis weed ( Zimmermann 1991), and the species can be tested as a biocontrol agent of invasive Acacia or Prosopis spp. , the latter becoming recently naturalized in South Europe ( Pasiecznik 2018).