Abstracts (first author)

Poster 

Fitness effects of warning signals through different life-stages and phenotypes

Author(s): Galarza JA, Suisto KH, Mappes J

Summary:

Many plants and animals advertise their unpalatability through warning signals in the form of colour and shape. A trade-off is inevitably faced to either allocate resources to signal efficiency or to other processes such as thermoregulation (i.e. melanin production). In the case where organisms undergo different phenotypes throughout their lifespan, such as Lepidopterans, it is unclear if allocating resources to warning signals in one phenotype can transfer fitness advantages to the next phenotype. Here we address this question by rearing full-sib tiger moth larvae (Parasemia plantaginis) in high and low temperature conditions and follow their warning signal development until adulthood. Subsequently, we tested for fitness differences as measured by survival and adult heating and metabolic rates. Our analyses showed that larvae reared at low temperatures had higher survival rate and decreased their signal size along its development, producing more melanised body segments. However, adults reared in higher temperatures had higher amount of melanin in their thorax. No clear differences were observed in the amount of melanin in the fore and hind wings between treatments. Adults reared at high temperature had a faster heating rate. On the other hand, adults reared at low temperature needed longer heating time, but had higher body temperature when flying was engaged. No differences were found between metabolic rates between adults of both treatments. Overall, our results suggest that allocating resources to maximise fitness during one life phase or phenotypic stage, does not necessarily translates into higher fitness in the following stages.



Abstracts (coauthor)

Summary:

Most research on the adaptive significance of warning signals has focused on the colouration and patterns of prey animals. However, behaviour, odour and body shape can also have signal functions and thereby reduce predators’ willingness to attack defended prey. For example, European vipers all have a distinctive triangular head shape and they are all venomous. Several non-venomous snakes are known to flatten their heads (head triangulation) when disturbed. Also many Lepidopteran larvae enhance their resemblance to tree vipers by concealing their heads and inflating their thorax or abdomen to express a false, sometimes triangular-shaped head. Even though anecdotal evidence of significance of snake head mimicry is dated back to the Henry Bates (1862), the role of body shape recognition is rarely experimentally investigated. Here we present data from field experiments and show that the triangular head shape can be recognized and avoided by predators. We also discuss the significance of this finding on population dynamics of snakes and its application their conservation. The smooth snake (Coronella austriaca) is non-venomous endangered species. By head triangulation it mimics vipers (Vipera sp.) which are not always protected by law. Because vipers are heavily killed by humans, it is possible that this asymmetric conservation program will be flawed because deceptive mimicry only works if the relative density and frequency of model species is higher than mimics. Based on the experimental evidence, we suggest that vipers should be protected at least in the locations where they co-exist with endangered mimic species.

Contacts

Chairman: Octávio S. Paulo
Tel: 00 351 217500614 direct
Tel: 00 351 217500000 ext22359
Fax: 00 351 217500028
email: mail@eseb2013.com

Address

XIV Congress of the European Society for Evolutionary Biology

Organization Team
Department of Animal Biology (DBA)
Faculty of Sciences of the University of Lisbon
P-1749-016 Lisbon
Portugal

Website

Computational Biology & Population Genomics Group 
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