Pseudolechriops
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| Champion , 1906 |
Pseudolechriops is a genus of beetles from the family of weevils (Curculionidae). It was described in 1906 on the basis of two individuals of the species Pseudolechriops megacephala by George Charles Champion. Around 20 species are now known. The relationships of the genus within the subfamily of the Conoderinae have not yet been adequately investigated. The animals occur in the Neotropia , where their food plants, the ant trees( Cecropia ), also grow.
features
The beetles have a broad head and an almost straight, flattened rostrum (Latin: "trunk"). The pronotum is short and almost cylindrical in shape. The compound eyes have a relatively large distance from one another. The sexes of most species can be distinguished on the basis of external characteristics.
Within the genus, a distinction is made between two groups of species. The Megacephala group, which includes the species Pseudolechriops megacephala , mostly includes black-colored animals, whose body has the shape of a rhombus when viewed from above . The tibiae of the hind legs are laterally flattened and more or less curved in the rear part. The males differ from the females by their differently shaped rostrum. The representatives of the Coleyae group are mostly reddish brown in color and have a slimmer build than the species of the other group. The tibiae of the hind legs are almost cylindrical in shape and the males have either the same or almost the same shaped rostrums compared to the females. The two groups seem to differ morphologically from each other to such an extent that they could be regarded as separate genera, but not only because the larvae are very similar in their way of life, the species Pseudolechriops klopferi has characteristics of both groups. The species within the two groups can be distinguished mainly by their hairiness, the color of the legs and the shape of the rusts.
Pseudolechriops presumably mimics the appearance of Azteca ants that live on the ant trees. They not only have a clear resemblance to these, but can also often be found sitting between them on the underside of the leaf.
Way of life
Larvae of all known species feed on fresh or dead leaf stalks of the ant trees. Almost all species of trees live in a symbiosis with ants called myrmecophylaxis , especially the Azteca genus . The plants form, among other things, protein- and fat-rich Müllerian bodies on the hair pads (trichilium) on the underside of the leaf roots, which are eaten by the ants. The adults of the beetles prefer to stay on the underside of fresh leaves and are less likely to be found feeding on Müller's bodies.
The individual species of the Pseudolechriops are strongly adapted to only one species of the ant trees. Only Pseudolechriops howdenorum was found on dry stems of two species, namely Cecropia insignis and Cecropia obtusifolia . Furthermore, the specialization concerns the age of the plants. For example, damage caused by Pseudolechriops wrightae could be found on around 60% of the stems of old Cecropia hispidissima plants, none was found on young ones. In Cecropia obtusifolia , Pseudolechriops coleyae behaved in exactly the opposite way, only traces were found on young plants. The selection based on the age of the trees is likely to be related to the way of life of the Azteca ants, but the exact relationships have not yet been explored.
Based on the way the larvae live in dead or fresh leaf stalks, the two groups mentioned above differ again.
The females of the species living on fresh stems lay their eggs in notches measuring about 0.25 millimeters in diameter, which are eaten directly on the trichilium of young leaves in the stems. One to four laid eggs or larvae in the first instar were found per stem, but adult larvae are always found alone. This suggests that older larvae compete with each other until only one remains. But this is just as unclear as the question of whether the eggs are laid by different or the same female, the former being more likely. The larvae live within the stems, where they migrate up and down and eat the nutrient-poor tissue or pulp along their entire length. Occasionally, neighboring, nutrient-rich cells are also eaten. The leaf is not affected by the feeding. The development of the animals takes about three months, three to four months is also the average lifespan of an ant tree leaf. Before pupation, a pupa chamber is built, which is closed on both sides by feces. This chamber can be located along the entire stem.
The larvae of species living on dead stems do not live along the entire stem, but predominantly in its thickened, woody base. The woody stalks of older leaves rot much more slowly and also offer more protection from predators, which is why they are preferred. The doll chamber is also built in the stem base.