Sennius crudelis Ribeiro­Costa & Reynaud

Caron, Edilson, Ribeiro-Costa, Cibele S. & Linzmeier, Adelita M., 2004, The egg morphology of some species of Sennius Bridwell (Coleoptera: Chrysomelidae: Bruchinae) based on scanning electron micrographs, Zootaxa 556, pp. 1-10 : 2-3

Sennius crudelis Ribeiro­Costa & Reynaud

Eggs laid singly, elongate, 0.88 mm in length and 0.25 mm in width (n=10), slightly enlarged on one end ( Fig. 1 ) and covered by a membrane, not ornamented ( Fig. 2 ). There are two bands of anchoring strands on each side, one internal and with shorter strands and other external with longer strands; all of them with an area enlarged near surface to form a homogeneous adhesive flange ( Figs. 1, 3 ). Two others elongate strands are placed at each end of the egg and also have the function of attaching the egg to the surface ( Fig. 4 ). The size of the egg and flange together are 1.46 mm in length and 0.40 mm in width (n=10).

The elongate form of the egg is similar to that of Pachymerus nucleorum (Fabricius) , some Acanthoscelides Schilsky and some Sennius ( Bondar 1937; Terán & L’Argentier 1979; L’Argentier & Terán 1980; Wightman & Southgate 1982; Ribeiro­Costa & Costa 2002). Terán and L’Argentier (1979) when describing the egg of S. laminifer , wrote that the egg enlargement corresponded with the size of the larva head.

Egg anchoring strands are common in Sennius . Bondar (1937) commented that the eggs of Sennius lateapicalis , S. subdiversicolor and S. laminifer have two elongated anchoring strands at each end and it is surrounded by numerous anchoring strands. Center and Johnson (1973) observed numerous anchoring strands on the eggs of S. morosus and S. simulans , while eggs of S. medialis have only two anchoring strands at each end. Ribeiro­ Costa and Costa (2002) also observed that eggs of Sennius leptophyllicola are surrounded by numerous anchoring strands.

Anchoring strands appear in eggs of other genera of Bruchinae, like Caryedes minor (Pic) , Merobruchus julianus (Horn) , Acanthoscelides bicoloripes (Pic) and A. nigronotaticeps (Pic) ( Bondar 1931, 1937; Forister & Johnson 1970; L’Argentier & Terán 1980).

Figures

FIGURE 1 – 4. Scanning electron micrographs of Sennius crudelis Ribeiro­Costa & Reynaud egg: (1) general view; (2) membrane covering the egg; (3) lateraly anchoring strands; (4) end anchoring strands.