Phylogénie Et Evolution Du Comportement Social Chez Les Blattes ...

Ev o l u t i o n d u c o m p o r t e m e n t s o c i a l1981)? Behavioral studies are needed to answer these questions and provide a robust basisfor understanding the evolution of social behavior in a group of cockroaches, both from field(Grandcolas, 1993a; Grandcolas and Deleporte, 1994) and laboratory perspectives, and froma phylogenetic point of view (Grandcolas, 1993b, 1993c, 1995, 1997b, 1998b; Pellens et al.,2007a, 2007b).Therefore, the purpose of the present study is to provide a description of behavioralinteractions at the individual level in closely related subsocial, gregarious and solitary speciesof the subfamily Zetoborinae to answer these questions.MATERIALS AND METHODSBiological materialThe selection of representatives of the subfamily Zetoborinae with different socialsystems was based on the results of field studies (Roth, 1973; Schal and Bell, 1985; Schal etal., 1984; Grandcolas, 1991, 1993a). Five species have been kept in the laboratory, namelyThanatophyllum akinetum (T.a.), Lanxoblatta emarginata (L.e.), Phortioeca nimbata (P.n.),Schultesia lampyridiformis (S.l.) and Parasphaeria boleiriana (P.b.). Cultures of the firstfour species were maintained at high and similar densities in plastic boxes (20 x 12 x 12 cm),with laboratory dog food and water ad libitum, relative humidity 90 %, temperature 25 ± 2°C and 12H/12H photoperiod. P.b. was kept in similar plastic boxes with the dead wood onwhich they feed. Cultures of the first three species originated from field samples from FrenchGuiana. The two latter species were obtained from a stock from Manaus and Espírito Santo,respectively, in Brazil (Roth, 1973; Pellens et al., 2002). Voucher specimens were deposited inthe Muséum national d’Histoire naturelle, Paris.As to their field habits, T.a. was found to inhabit terrestrial litter. Its distributionand the spacing behavior of young larvae in the understory of tropical rainforest is stronglyindicative of solitariness (actually, the only solitary species known from this subfamily).L.e. and P.n. were observed to shelter under the loose bark of dead and living trees,318