PCA analysis Fig. S2 revealed a trend toward ALB from the second day after injection, which was significant only on the fourth day. By contrast, isolated animals injected with either saline or 0.
Effects of ecdysteroids. The results Ai showed that the percentage of time spent in the light arms during the first 3 days 1st day: The retreat ratio Aii progressively increased over the 3 days after injection 1st day: 0. These observations suggest that 20E is able to modulate ALB. However, 20E probably does not act on ALB through a rapid and direct effect but through a delayed and possibly indirect effect. This hypothesis may explain why low doses of 20E are inefficient, as well as why the first signs of ALB appeared during the natural molting cycle in late pre-molt but not early pre-molt.
Numerous studies have shown that ecdysteroid titers increase progressively during early pre-molt and decrease in late pre-molt Stevenson et al. Although we have not analyzed the kinetics of ecdysteroids after 20E injection, we can assume that our experiments partly mimic both the increase and the decrease of ecdysteroid titers during pre-molt: indeed, the injection of ecdysteroids into crustaceans is followed by the rapid elimination of exogenous hormones and their metabolites into urine Snyder and Chang, Thus, a control of ALB after a decrease in ecdysteroid titers can be hypothesized, and whether peptides or other hormones could be intermediate hormonal regulators of ALB remains an open question.
The results Fig. These data confirmed that the changes in behavior induced by ecdysteroids were really related to anxiety. They also confirmed that 20E-related ALB was not due to a deleterious effect of the hormonal injection.
Suppression of anxiety-like behavior ALB by a benzodiazepine. In agreement with Fig. In conclusion, crayfish molt involves a transitory light-aversion behavior that can be related to anxiety, because of its sensitivity to benzodiazepines, and that is controlled by ecdysteroids through a long-term effect. These observations are probably generalizable to many arthropods.
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Sign In or Create an Account. Advanced Search. User Tools. Sign in. Skip Nav Destination Article Navigation. Close mobile search navigation Article navigation. Volume , Issue 2. Previous Article Next Article. Article contents. Article Navigation. Do arthropods feel anxious during molts? This site. Google Scholar. Marion Berthomieu Marion Berthomieu.
Daniel Cattaert Daniel Cattaert. Pascal Fossat Author and article information. Competing interests The authors declare no competing or financial interests. Received: 19 Jun Accepted: 30 Nov Online Issn: Published by The Company of Biologists Ltd. J Exp Biol 2 : jeb Article history Received:. Related content. Read up on the basics of molting. The laws of physics and inheritance. Molting and the exoskeleton: Squishy crabs.
Subscribe to our newsletter. Email Facebook Twitter. Here we see a cicada emerging from its molted exoskeleton. The largest wild sheep in North America are the bighorn sheep. They shed their heavy winter coats every June and July, when the weather warms up. Molting helps them avoid heat stress in the summer.
It also helps them to more easily navigate the rugged regions high up in the mountains. A percent is a ratio that compares a number to When you know the part and a whole, you can use them to calculate a percent. Use the information to answer questions about how different animals molt. Round your answers to the nearest whole percent. Record your work and answers on our answer sheet. In its first year, a Dungeness crab molts 6 times.
If a Dungeness crab can live up to 13 years, what percent of its total expected life span has a 3-year-old crab reached? The long-horned grasshopper spends up to days in the nymph stage, when it undergoes molting. What percent of its day-long lifetime does it spend as a nymph? An American grasshopper weighs 10 milligrams as a new nymph. If a rattlesnake has 18 rattles, and shed its skin 7 times in its first year of life, what percent of shedding occurred that first year? In its first year, a king cobra sheds its skin once every month.
If a shedding cycle takes about 1. Hint: There are 52 weeks in a year. A male Merino sheep weighs about pounds and produces 25 pounds of wool. A female weighs about pounds and produces 18 pounds of wool. Which produces a greater percent of its body weight in wool? Contact Us. What You Get. Editorial Calendar.
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