Description of Larvae of the Genus Formicomus Laferté, and Data on the Life Cycles of Omonadus floralis (Linné) and Notoxus monoceros (Linné) (Coleoptera: Anthicidae)

The larvae of Formicomus pedestris Rossi, F. gestroi Pic, and F. rubricollis Laferté (Coleoptera: Anthicidae, Anthicinae) are described and biological data of the reared larvae are given. The life cycles of Omonadus floralis (Linne´) and Notoxus monoceros (Linne´) are illustrated, and notes of breeding experiments with Stricticomus amaniensis Pic are added. Data on the larval stages of Anthicinae beetles are rare.

Presently the larvae of 11 genera of this subfamily are known: Anthicus Paykull, Cyclodinus Mulsant & Rey, Formicilla LeConte, Ischyropalpus Laferte´, Malporus Casey, Mecynotarsus Laferte´, Notoxus Geoffroy, Omonadus Mulsant & Rey, Tanarthrus LeConte, and Vacusus Casey (Rey 1887; Böving and Craighead 1931; Bonadona 1958; Bucciarelli 1980; Kitayama 1982; Colombini et al. 1985). Larvae of Anthicinae are characterised by one pair of stemmata, and usually a single pair of median endocarinae of the head capsule.

An autapomorphy is the so-called penicillus (setae) at the bases of the mandibles. In the subfamiliy Ischaliinae, which were transferred from Pyrochroidae to Anthicidae by Lawrence and Newton (1995), a penicillus is also present (Young 1985), which however might also be an analogous structure as most of the other characters of this group differ very much from Anthicidae (Hemp, unpubl. data). Anthicids lack urogomphal pits, which are present in members of the related family Pyrochroidae (Young 1991; Kitayama 1982).

Some genera of Anthicinae are obviously associated with sandy habitats, like many species of Notoxus and Mecynotarsus. The larvae live in the upper surfaces of the soil feeding on decaying material (Young 1991), but N. monodon (Fabricius) may bore into sweet potato tubers (Cuthbert 1967). Larvae of Anthicus species have been observed to feed on eggs and pupae of other insects like beetles and dipterans (e.g., Chandler 1977; Kitayama 1982).

Adults of Formicomus rubricollis LaFerté and F. gestroi Pic gather on Lepidium bonariense (Brassicaceae) to feed on the sporangia of a mildew fungus, but they can be easily reared also with any other kind of food like bread, fish food, fruit, and dead insects, such as specimens of their own species. Their larvae may be found by sieving the upper soil layers in cultivated areas, and reared in earth fertilized with cow manure (Hemp et al. 1997).

Methods and Materials Adult beetles of Formicomus pedestris Rossi, F. rubricollis, and F. gestroi were collected at cantharidin baits (Hemp et al. 1997). F. pedestris was attracted in a wheat field in Istria/ Yugoslavia, while F. rubricollis and F. gestroi were baited in a meadow with sparse vegetation on the southern slopes of Mt. Kilimanjaro, Tanzania, at an altitude of 1,430 m.

In the same area as F. rubricollis and F. gestroi, Stricticomus amaniensis Pic was living on patches of ground devoid of vegetation. Specimens of this non-canthariphilous species were collected with the aid of an aspirator. 361 The beetles were kept in glass rearing jars, covered with porous gauze, in the laboratory. The bottom of each jar was covered with cellulose paper.

Some shallow plastic boxes filled with soil, taken from the habitats of the different species were also on the bottom of the jar. The adults were fed a diet of fish food, bread, and pieces of fruit. The rearing jar was sprayed daily with water to maintain the proper humidity.

Eggs were found by viewing the soil of the shallow plastic boxes with binoculars and then isolated into small petri dishes to obtain freshly hatched larvae for further investigation. A high hatching rate was obtained with a humidity of nearly 100% and a constant temperature of 25 º C. The larvae hatched between the 10th and 12th day. Freshly hatched larvae (L1-stage) of most species were taken for morphological investigation (Olympus automatic photomicrographic microscope; Scanning electron microscopy (SEM), Cambridge 90S, film: Agfapan 25).

For Notoxus monoceros and Omonadus floralis the larval stage could not be determined as rearing of larvae from eggs failed and larvae were taken out directly from the shallow plastic boxes filled with soil.