Note sulla presenza di Batrisodes oculatus Aubè (Coleoptera, Pselaphidae) in una grotta di Puglia

Abstract

NOTES ABOUT THE PRESENCE OF Batrisodes oculatus AUBÈ (Coleoptera, Pselaphidae) IN A CAVE IN APULIA

Explorations of a large karstic cave in Apulia (« Grotte di Pozzo Cucù», Castellana) have shown a rich presence of Batrisodes oculatus in the deeper parts of this cave, where many alive adults have been collected and some hundreds of died specimens observed, lots of which scarcely sclerotized.

Then decomposing vegetable baits have caused concentration of adults, feeding on Col- lembola, and have supplied substratum for development of larvae.

The authors give here some data about the behaviour of adults and larvae in laboratory conditions; they describe preliminarly the morphology of the third-instar larva and segnalize the presence of complex antenna! glands in males.

Moreover, the following points are discussed:

a) Causes of the presence of the species in the cave - Because the country upon the cave does not show the usual environment of this species (i.e., old trunks of trees popu- lated by Lasius ants, or wood litter), it may be that the cave environment has allowed a population of B. oculatus surviving there, despite the distruction of the woods.

b) Comparison between the cave specimens and those collected in woods - Neither reduction in pigmentation, nor lengthening of appendages have been recognized.

c) Numerica! ratio males/females - In total, a moderately higher number of females has been collected (58 ♀ ♀ 38 ♂ ♂ ). In Authors' opinion, a different mobility of the two sexes within their environment may cause such a lack of numerica! balance.

In conclusion, B. oculatus can be classified as troglophile species, because it lacks clear adaptations to subterranean environment, but it is clearly able to spend its own life cycle in caves.