O aparelho Saltatório do Halticíneo Homophoeta sexnotata Har. (Coleoptera)

Abstract

Descreveu-se o mecanismo saltatório do Halticíneo Homophoeta sexnotata. O aparelho se encontra localizado no fêmur e consta de uma placa cuticular arqueada, em forma de S, e, de uma placa menor, triangular. Tôdas as placas representam modificações dos tendões do abdutor e flexor da tíbia e mantêm ainda ligação com os mesmos. Pela colaboração das duas placas acumula-se uma forte tensão no tendão do abdutor (músculo saltatório). A tíbia não se pode esticar pois a placa trinagular fica presa numa cavidade da parede do fêmur. Apenas no momento da maior contração do abdutor a placa curvada força a saida da placa triangular do seu ponto de apóio. Desta maneira o forte músculo abdutor da tíbia exerce tôda a sua força, de uma só vez, sôbre a articulação da mesma, dando ao Coleóptero um forte impulso para saltar. O órgão é encontrado em grande número dos Halticíneos. em homenagem ao grande entomólogo brasileiro PROF. DR. ANGELO DA COSTA LIMA dei ao órgão o nome de ÓRGÂO DE COSTA LIMA.

Jumping mechanisms and performance in beetles. I. Flea beetles (Coleoptera: Chrysomelidae: Alticini)

“…Functional aspects of the TFS proposed by Furth and Suzuki (1990a) and Gorb (1995) are: (1) strengthening of the base for the flexor tendon; (2) increasing the working angle of the leg flexor system; and (3) protection of the ventral side of the exposed femorotibial joint. Barth (1954), based on the studies of the flea beetle Homophoeta sexnotata Harold 1876, and later Betz et al (2007: figs 11, 12), based on SR-µCT findings in Altica sp., proposed that the TFS may serve as a key part of a catching mechanism preventing the premature extension of the tibia during the co-contraction of both the flexor and the extensor muscles. According to this model, the catching mechanism might be accomplished by pressing the TFS against the distal margin of the posterior femoral wall that forms an abutment (Betz et al, 2007: figs 11 and 12E-G).…”

“…Anatomically, it provides attachment points for extensor muscles (Maulik, 1929;Furth, 1980;Schmitt, 2004). Hypotheses about the mechanism of jumping in flea beetles were presented in the works of Barth (1954) and Ker (R. F. Ker, Some structural and mechanical properties of locust and beetle cuticle, PhD thesis, Oxford University, 1977), and summarized in Furth (1988). The studies of Furth (1982Furth ( , 1988 and Furth et al (1983) were focused on the intergeneric comparative morphology and the anatomy of the modified metafemoral extensor tendon (MET), the so-called 'metafemoral spring' or 'metafemoral apodeme'.…”

“…In brief, the flexor muscles adduct the tibia, then the flexor and the extensor muscles co-contract, the extensor muscles contract the MET and the energy of contraction is accumulated in the MET. A triangular flexor sclerite (Lever's triangular plate) connected to the tibial base serves as a locking mechanism (corresponding to the functional model proposed by Barth, 1954) to prevent the extension of the tibia during the co-contraction of the more powerful extensor muscles over the flexor. According to this model, the locking mechanism might be accomplished by pressing Lever's triangular plate against the distal margin of the posterior femoral wall that forms an abutment (Betz et al, 2007, fig.…”

The Hot-Blooded Insects

“…Rudolf Barth (1954) first correctly inferred that the flea beetle Homophoeta sexnotata gets its energy for the jump by contracting the massive muscles in its thick hind femora. These muscles pull apart a stiff, S-shaped structure, the metafemoral spring ( Fig.…”

Inter‐generic differences in the metafemoral apodeme of flea beetles (Chrysomelidae: Alticinae)

“…Maulik speculated that any chrysomelid with this structure was an alticine and any such taxa that could not jump showed degeneration of the organ. This structure is usually called Maulik's Organ (Scherer, 1971), but it has been called Costa Lima's Organ (Barth, 1954), and extensor apodeme (Wilcox, 1965). I prefer to call it the metafemoral apodeme ( Fig.…”