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Effect of gravidity on jump performance and muscle physiology in the American locust
Author(s) -
Carroll John P.,
Kirkton Scott D.
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.714.4
Subject(s) - jumping , jump , contraction (grammar) , grasshopper , biology , anatomy , muscle contraction , electromyography , orthoptera , zoology , medicine , endocrinology , physiology , ecology , physics , quantum mechanics , neuroscience
The effect of gravidity (or load) on jumping is not well documented. Lizards produced shorter jumps when a load equal to 30% of body mass was attached. However in Schistocerca americana grasshoppers, 20% heavier gravid females have the same jump distance as non‐gravid females. We tested the hypothesis that grasshoppers increase their jumping muscle contraction duration when gravid (or loaded). We examined the effect of added mass on jump performance by attaching weights (20% or 40% of body mass) to gravid females, non‐gravid females, and males. We used high‐speed video analysis to compare jump performance and electromyography to measure jumping muscle contraction times. Results indicate that muscle contraction duration increased 20% from non‐gravid to gravid females. When an additional weight equal to 20% of body mass was attached, muscle contraction duration increased by over 30% for all grasshoppers. Further loading (40% of body mass) caused muscle contraction duration to increase 130% from un‐loaded controls in both males and gravid females, but it increased over 200% in nongravid females. These results suggest muscle contraction duration is proportional to load. Increasing muscle contraction time would allow grasshoppers to store more energy in their catapult mechanism prior to jumping, thereby allowing gravid females to have the same jump distance as non‐gravid females.