QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online October 5, 2007
Journal of Experimental Biology 210, 3590-3600 (2007)
Published by The Company of Biologists 2007
doi: 10.1242/jeb.009100

This Article Summary Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Burrows, M. Search for Related Content PubMed PubMed Citation Articles by Burrows, M. Social Bookmarking                         What's this?

Anatomy of the hind legs and actions of their muscles during jumping in leafhopper insects

Malcolm Burrows

Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK

View larger version (90K): [in this window] [in a new window]   Fig. 1. Drawings of joints in the hind leg critical for jumping. (A) The proximal hind leg joints of Aphrodes as viewed ventrally. The left hind leg is shown fully levated, and the right hind leg almost fully depressed. (B) Femoro-tibial joint of a large unidentified Cicadellid from Venezuala. Prominent ridged spines project dorsally and laterally from the end of the femur. The ventral coverplate is notched but the surrounding area is not heavily sclerotised. The tibia has rows of prominent lateral spines. (C) Ventral view of the distal tibia and the tarsus to show the arrays of short spines at the tibio-tarsal joint and at the joints of the tarsus. (D) Side view of Aphrodes to show the greatly enlarged coxa of the right hind leg compared to that of the other two legs. The distal parts of the legs are omitted in A and C. Scale bars, 200 µm.

View larger version (160K): [in this window] [in a new window]   Fig. 2. Scanning electron micrographs of Empoasca to show the organisation of the joints of a hind leg and some of their associated proprioceptors. (A) The left half of the body, as viewed ventrally and with anterior at the top. The left hind leg is fully levated about the coxo-trochanteral joint and the distal part of the femur bearing a group of spines fits into a sculpted region of the head capsule. The proximal part of the femur is pressed against a hair row on the coxa. Parts of the left, middle leg distal to the trochanter, and parts of the left, front leg distal to the coxa have been removed to reveal the hind leg more clearly. Scale bar, 250 µm. (B) Further detail of the area in A outlined by the top broken box, to show the engagement of the femoral spines with the sculpted region of the head capsule when the left hind leg is fully levated. Scale bar, 100 µm. (C) Detail of the area in A outlined by the lower broken box to show the proximal femur pressing against the hair row on the coxa (black arrow) when the leg is fully levated. Scale bar, 100 µm. (D) Structure of the hairs (within the broken box in C) making up the hair row. Scale bar, 10 µm.

View larger version (140K): [in this window] [in a new window]   Fig. 3. Scanning electron micrographs of Aphrodes to show possible proprioceptors associated with the proximal joints of a hind leg. (A) Lateral to the hair rows on the coxa are two hair plates (black arrows) in the hollowed region of the coxa that will accommodate the femur when the leg is fully levated. A small group of long hairs (black arrow) project posteriorly from the posterior and medial region of the coxa. A hair plate (white arrows) is present on the lateral surface of a ventral horn of a trochanter as it articulates with a coxa. Scale bar, 200 µm. (B) Detail of the two coxal hair plates from the leg on the right (top broken box) in A. Scale bar, 100 µm. (C) The trochanteral hair plate, again from the leg on the right (lower broken box) in A. Scale bar, 20 µm. All photographs in A–C are of ventral views with anterior at the top. (D) Dorsal view of the trochanter to show two long hairs. Note also that the dorsal femur has no protrusion. Scale bar, 200 µm. (E) The boxed region in D at higher magnification. Scale bar, 100 µm.

View larger version (155K): [in this window] [in a new window]   Fig. 4. Scanning electron micrographs of Cicadella to show the mechanical linkages between the medial surfaces of the hind coxa. The legs were pulled apart before fixation to show the structures involved; ventral views with anterior at the top. (A) Low power, of the two coxae, with the coxo-trochanteral joint on the left more levated than on the right. The white arrows indicate a medially directed protrusion from the coxa on the right and a corresponding socket in the coxa on the left with which it engages. Scale bar, 200 µm. (B) Higher magnification view from the same perspective to show the protrusion and socket, and two arrays of microtrichia on each coxa. These two arrays will also engage the corresponding arrays on the other leg, when the coxae are apposed to each other. Scale bar, 50 µm.

View larger version (169K): [in this window] [in a new window]   Fig. 5. Mechanical linkages between the hind coxae. (A,B) The two hind coxae of Cicadella were separated and then mounted so that their inner faces point toward the observer. The anterior midline is therefore between the two pictures and the posterior midline is at their lateral edges. If the two pictures are folded toward each other along the vertical white bar separating them, then the protrusion (in this insect on the left) and socket (on the right), and the two fields of microtrichia engage with each other. Scale bar, 50 µm. (C) No press stud is present in a nymphal stage of Iassus lanio. Scale bar, 200 µm. Ventral view with anterior at the top.

View larger version (48K): [in this window] [in a new window]   Fig. 6. Anatomy of the muscles moving the coxo-trochanteral joint of a hind leg of Aphrodes. (A) Ventral view with the left hind leg shown fully levated, and the right hind leg partly depressed. The trochanteral depressor muscle of each hind leg is medial and the different parts of the levator muscle are more lateral. (B) Side view of the right metathorax exposed to show the laterally placed trochanteral levator muscles of the right hind leg in a depressed position. Scale bar, 500 µm.

View larger version (97K): [in this window] [in a new window]   Fig. 7. Movements of the coxo-trochanteral joint of Aphrodes. (A–C) Ventral views of the joint if the left hind leg is forcibly moved (blue arrows) into different positions from fully levated (A) to almost fully depressed (C). The right hind leg remains in the same partially depressed position throughout. Scale bar, 200 µm. (D) The lever arms of the trochanteral depressor and levator muscles plotted over the full range of coxo-trochanteral movements.

View larger version (35K): [in this window] [in a new window]   Fig. 8. Actions of hind leg trochanteral muscles of Aphrodes during jumping. Simultaneous recordings from trochanteral depressor (upper trace) and levator (lower trace) muscles of the right hind leg during a jump. Selected frames of the leg movements from high-speed images are shown above at the times indicated in this and Figs 10, 11 (scale bar on right frame, 1 mm). The activity in the two muscles began when both hind legs were already levated and resulted in an anterior movement of both (horizontal lines). The activity in the depressor increased before the jump movement while that in the levator declined.

View larger version (26K): [in this window] [in a new window]   Fig. 9. Recordings from the trochanteral depressor muscle of the right hind leg during five jumps by the same Aphrodes. The timings of the jump movements were recorded with high-speed images. The duration of the muscle activity ranged from 20–160 ms.

View larger version (48K): [in this window] [in a new window]   Fig. 10. Simultaneous recordings from the trochanteral depressor muscles of the left and the right hind legs of Aphrodes. (A) The rapid and simultaneous jump movements of both hind legs (arrows) were preceded by a high frequency burst of spikes in both depressor muscles. Scale bar on left frame, 1 mm. (B) Displaying this burst of spikes (between the broken lines in A) on a faster time scale showed that the spikes on the two sides were not tightly coupled.

View larger version (51K): [in this window] [in a new window]   Fig. 11. Independent movements by the two hind legs. Simultaneous recordings were made from the trochanteral depressor muscles of the left and the right hind legs of the same Aphrodes as Fig. 10. (A) A rapid kick by the right hind leg alone was preceded by a burst of spikes only in the right depressor muscle. Scale bar, 1 mm. (B) The burst of spikes on a faster time scale.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

Twitter