Asian Hornet-Cacynen Asia

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Asian Hornet

Cacynen Asia

Asian hornet (Vespa Velutina) is a particular threat to honey bees, unlike our own European hornet (Vespa Crabro). The Asian hornet is slightly smaller than its native counterpart, with adult workers measuring from 25mm in length and queens measuring 30mm. They have a mostly dark brown or black velvety body except for the fourth abdominal segment which is a conspicuous yellow band near to the rear. The brown legs have yellow ends, which is why it is often called the yellow legged hornet, while its face is orange with two brownish red compound eyes.

When predating on honey bees, hornets can be seen hovering outside a hive entrance, waiting for returning foragers, this is the characteristic “hawking” behaviour. As the colony expands and the nest size increases, it is either built around the queen’s embryonic nest or the colony relocates and finds a new site to build, often high in tall trees and increasing up to a metre in diameter.

Reporting leads

The way to report Asian hornet sightings is via the Asian Hornet Watch app. or by an alert email – alertnonnative@ceh.ac.uk or on the online recording form on the NNSS website
http://www.brc.ac.uk/risc/alert.php?species=asian_hornet

Mae cacynen Asia (Vespa Velutina) yn fygythiad neilltuol i wenyn mêl, yn wahanol i’n cacynen Ewrop ni (Vespa Crabro). Mae cacynen Asia ychydig yn llai na’r un frodorol, gyda’r gweithwyr aeddfed yn mesur o leiaf 25mm o hyd a breninesau’n mesur 30mm. Mae eu cyrff melfedaidd yn frown tywyll neu’n ddu, gan fwyaf, heblaw am bedwaredd gylchran yr abdomen, sydd â chylch melyn amlwg yn agos at y rhan ôl. Mae’r coesau brown yn felyn tua’u blaenau (dyna pam y’i gelwir yn aml yn gacynen goesfelen), ac y mae’i hwyneb o liw oren gyda dau lygad cyfansawdd brown-goch.

Wrth iddynt geisio dal gwenyn mêl, gellir gweld cacwn yn hofran y tu allan i fynedfa cwch, yn disgwyl i wenyn ddychwelyd o’u helfa. Mae hwn yn ymddygiad “cudyllaidd” nodweddiadol. Wrth i’r haid gynyddu a maint y nyth gynyddu, yna ynteu y’i llunnir o amgylch nyth embryonig y frenhines neu mae’r haid yn symud ac yn canfod rhywle arall ar gyfer adeiladu, yn aml yn uchel i fyny yng nghoed tal, a chan gynyddu hyd at fedr ar draws.

Rhoi gwybod amdanynt

Dull rhoi gwybod am weld cacwn Asia yw trwy’r ap Asian Hornet Watch neu e-bost rhybuddiol – alertnonnative@ceh.ac.uk neu ar y ffurflen gofnodi ar-lein ar wefan yr Ysgrifenyddiaeth Rhywogaethau Estron (NNSS)
http://www.brc.ac.uk/risc/alert.php?species=asian_hornet