Insects on fronds

Crowson (1989) has mentioned on Maro%amia fronds, in Australia, buprestids, such as Xyroscelis rocata and X. bumanna. The sagrine, Carpoph-agus banksiae, which looks like a big bruchid, has been also found on the fronds of Maro%amia. The relationship of these insects with cycads has not been fully elucidated.

Really, there are many frond frequenting insects on the cycads, in tropical America as well as in South East Asia. Good observations in Africa are lacking, as well as in Madagascar. We must observe the time of appearance of these insects, which have only a short adult life, most of their life being in the larval stage.

In South East Asia, Lilioceris, normally a Liliaceae feeder, frequents also local cycads. In New-Guinea, Szent-Iwany et al. (1956) has been the first to mention Lilioceris clarki (Baly) on the new fronds of Cycas circinnalis. Later on, Hawkeswood (1992) recorded Lilioceris nigripes (Fabricius) in Queensland on the forest dwelling species Bowenia spectabilis Hook, a Zamiaceae. There were similar captures in Vietnam, and Shepard (1997) has reported an undetermined species of Lilioceris on the fronds of Cycas siamensis Miquel in Thailand in a Dipterocarpus forest. Larvae were localized under leaflets, and were browsing the abaxial epidermis and a part of the mesophyll. These larvae, as also the adults, were red, very prominent over the dark greeen foliage. Cycas celebica Braun, the unique and rare cycad in New Caledonia, does not seem to harbour any criocerine, and the local beetles of this leaf beetle subfamily have been captured there on orchids only.

Aulacoscelis spp. (Chrysomelidae, Aulacoscelinae) also rasp young and new tender green fronds of several Zamia species, to suck up sap. They are mostly common in Central America, after the spring rains. Adults migrate over the mountains of Panama (El Cope), probably looking for new plants. In Central America, they are often in company of the caterpillars of Eumaeus minyas and E. godarti (Lycaenidae) and the langurid, Nomotus lateralis. Langurids and Aulacoscelis seem to rasp the leaves, partly for pharmacophagy, as toxicity of the cycads protects them from predators. Being very toxic they are never attacked by ants or other predators. Nomotus is black and Aulacoscelis is orange-red and both are aposematic. The Eumaeus, in contrast to many Lycaenids, are not associated with ants. Their own acquired toxicity protects them very well. The larva of Aulacoscelis has been recently described by Cox and Windsor (1999). Its biology is unknown, but with what we know at present of Janbechynea, a big aulacosceline, we could suspect a development inside the seeds in the cones. This aspect is actually under study.

It seems very probable that during the Jurassic the Protoscelinae were feeding on Cycadales or Bennetitales. The remains of those plants are contemporaries of these insects in the geological layers in Siberia. All first observations on aulacoscelines were done in Panama and Costa-Rica (Jolivet, 1998; Windsor and Jolivet, 1997; Windsor et al, 1999). There exist a dozen of species of Aulacoscelis in America and five species of Janbechynea. When fed in laboratory, they accept fruit juices, like mangoes, which means that juice sucking is part of their normal diet. Very probably Janbechynea feeds on cycads in Bolivia, and there is a high possibility that the larvae live inside seeds.

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