Jumping without Using Legs: The Jump of the Click-Beetles (Elateridae) Is Morphologically Constrained

To return to their feet, inverted click-beetles (Elateridae) jump without using their legs. When a beetle is resting on its dorsal side, a hinge mechanism is locked to store elastic energy in the body and releases it abruptly to launch the beetle into the air. While the functional morphology of the jumping mechanism is well known, the level of control that the beetle has over this jumping technique and the mechanical constraints governing the jumps are not entirely clear. Here we show that while body rotations in air are highly variable, the jumps are morphologically constrained to a constant “takeoff” angle (79.9°±1.56°, n = 9 beetles) that directs 98% of the jumping force vertically against gravity. A physical-mathematical model of the jumping action, combined with measurements from live beetle, imply that the beetle may control the speed at takeoff but not the jumping angle. In addition, the model shows that very subtle changes in the exact point of contact with the ground can explain the vigorous rotations of the body seen while the beetle is airborne. These findings suggest that the evolution of this unique non-legged jumping mechanism resulted in a jumping technique that is capable of launching the body high into the air but it is too constrained and unstable to allow control of body orientation at landing

Hyphantria cunea Drury, espèce d'origine américaine, fera-t-il bientôt partie de notre faune ? [Lep. Arctiidae]

d'Aguilar Jacques. Hyphantria cunea Drury, espèce d'origine américaine, fera-t-il bientôt partie de notre faune ? [Lep. Arctiidae]. In: Bulletin de la Société entomologique de France, volume 58 (1), janvier 1953. pp. 7-8

Contribution à l'étude des Diptères de France (2e note)

d'Aguilar Jacques. Contribution à l'étude des Diptères de France (2e note). In: Bulletin de la Société entomologique de France, volume 50 (4),1945. pp. 43-44

Nouvelles acquisitions

d'Aguilar Jacques. Nouvelles acquisitions. In: Bulletin de la Société entomologique de France, volume 62 (5-6), Mai-juin 1957. pp. 159-160

R. L. Usinger. — Aquatic Insects of California. Berkeley, 1956

d'Aguilar Jacques. R. L. Usinger. — Aquatic Insects of California. Berkeley, 1956. In: Bulletin de la Société entomologique de France, volume 62 (5-6), Mai-juin 1957. p. 160

Rémy Chauvin : Physiologie de l'Insecte (Editions de l'Institut national de la Recherche agronomique)

d'Aguilar Jacques. Rémy Chauvin : Physiologie de l'Insecte (Editions de l'Institut national de la Recherche agronomique). In: Bulletin de la Société entomologique de France, volume 55 (1), janvier 1950. p. 16

R. E. Snodgrass. — Manuel d'Anatomie des Arthropodes (A Textbook of Arthropod Anatomy). Ithaca 1952

d'Aguilar Jacques. R. E. Snodgrass. — Manuel d'Anatomie des Arthropodes (A Textbook of Arthropod Anatomy). Ithaca 1952. In: Bulletin de la Société entomologique de France, volume 59 (3-4), Mars-avril 1954. p. 47