Hymenoptera

K, Julia Baumann, 2024, An update on the knowledge about scutacarid mites as phoronts and inquilines, Acarologia 64 (1), pp. 3-17 : 7

Hymenoptera : Bees (Annex IV)

Scutacaridae don′t play an important role as associates of the honey bee Apis mellifera

(family Apidae ). Still, the third scutacarid species after Imparipes apicola (Banks, 1914) and

Scutacarus acarorum (Goeze, 1780) (Baumann 2018) was now encountered as inquiline of

A. mellifera by Abd El Hady and Mahfouz (2021). They found Scutacarus evansi Momen &

Curry, 1987 in bee hives in Egypt, albeit only in low abundance.

In different Bombus species (also family Apidae ), Scutacarus acarorum can be found

as a frequent associate. This mite species generally prefers hibernated queens as phoresy

host (Baumann 2018). It has now also been found associated with Bombus bellicosus and B.

pauloensis in Uruguay ( Revainera et al. 2019), and although authors state that the associated

acarofauna in general preferred queens as host, the prevalence of S. acarorum was highest in

males of both Bombus species in the respective study. Another species, Imparipes (I.) rafalskii

Dastych, 1978, was newly found associated with B. terrestris and also with the genus Andrena

of the family Andrenidae ( Sobhi et al. 2017a) . This scutacarid was until now only known

phoretic on the apid Dasypoda plumipes (Baumann 2018) .

Nazari et al. (2019) found an Imparipes species phoretic on either the genus Andrena

( Andrenidae ) or on Antophora ( Apidae ); the real host is unclear because the text and table 2 of

the respective publication are inconsistent with one another. If the host in fact Antophora is,

this would be the first report of this genus as host for Scutacaridae .

Until now, only two species of the scutacarid genus Nasutiscutacarus were known, N.

ampliatus Beer & Cross, 1960 and N. anthrenae Beer &Cross, 1960 , both of which are phoretic

on bees of the soil nesting family Halictidae (Baumann 2018) . This number was now doubled

by Khaustov and OConnor (2019), who described two new scutacarids associated with halictid

bees: N. latisetus Khaustov & OConnor, 2019 from Sri Lanka and N. longicaudus Khaustov &

OConnor, 2019 from Papua New Guinea. Nasutiscutacarus is characterized by an elongated

gnathosoma which implies a highly specific, albeit still unknown, feeding source ( Khaustov and

OConnor 2019). Since all known species of Nasutiscutacarus are associated with Halictidae ,

the elongated gnathosoma most likely is an adaptation to special conditions in the hosts’ nests.

However, other scutacarid genera possessing typical scutacarid gnathosomata can also be

encountered in association with Halictidae (Baumann 2018) , which indicates that it must be a

unique niche within halictid nests that is exploited by Nasutiscutacarus .