Delphacid planthopper - Flastena fumipennis - Dearne Valley - Old Moor & Dearne Valley

24 Sep 2022

Delphacid planthopper - Flastena fumipennis James Flanagan

Female Left, Male Right

Delphacid planthopper by the name of Flastena fumipennis. It was during my visit of 31^st August last year to RSPB Old Moor, in the later period of their season, when I found it. This species has been known for a while to occur on the Channel Islands. It is said to be widespread in the Mediterranean region but we are not really sure of its current status in the UK. It may be a species has been moving or shifting its range further north, perhaps for a long period of time, but it is not clear how the species has become established on the British mainland, whether from natural dispersal or aided through transport networks (i.e. that used for movement of horticultural produce). It is also possible that it may be an overlooked native but this is now impossible to verify with any certainty.

Our first mainland records came from two nearby locations in Cambridgeshire, the first during 2018 and then in August 2020. This was followed by three further records of populations in 2021; from locations in Sussex, Worcestershire and at RSPB Old Moor Wetland Centre. My efforts to search for further populations in the region this year have resulted in just one more, also located in South Yorkshire, at Elsecar Reservoir and Local Nature Reserve on 22^nd August. So far just six populations have been identified but there must be many more for the species to be present this far north. On the16^th September this year I checked out the patch of galingale present in the dragonfly ponds area of RSPB Old Moor and although conditions appear not to have changed since last year I found none to be present, so wondering if their season here has finished early for some reason.

Last year, when I swept the galingale, there were numerous adult males and females as well as some late stage nymphs. I attach a photo of a male from among a few of the specimens I collected. My ID based on photographs of male and female specimens (plus dissected male genitalia of one specimen) was confirmed by the organiser of the national recording scheme for Auchenorrhyncha (comprising cicadas, lace, plant, leaf and froghoppers) Dr Alan Stewart.

On 19^th September I also visited the Elsecar Reservoir site and found a good population of adults still present (see attached photo of long-winged female and male specimen which don’t have the dusky wings of the shorter-winged forms). On this visit I found the Cyperus more extensively present along the southern margin of the reservoir but mostly in more scattered clumps located by fishing platforms where only a few specimens were found to be present. I also noted that in the areas that had good numbers of adults there were also numerous early-mid stage nymphs. If these are, indeed, the nymphs of Flastena then it appears to be indicative of a second or even possibly a third annual generation. The species has been reported to be polyvoltine (certainly bi-voltine or tri-voltine), with the largest number of generations per annum probably produced in the southern part of its large range around the Mediterranean. The season for the species is between April and early October, it is more common in the later part of this period and it is reported to overwinter as a nymph in contrast to most Delphacids which overwinter in the egg stage (Della Giustina, 2019).

It is possible that F. fumipennis also utilises other Cyperus species and there are some locations in the region with non-native pale galingale (Cyperus eragrostis) that need to be sampled to verify this.

A joint paper is in preparation for the journal of the British Entomological and Natural History Society formally reporting this species as new to the British mainland.