ORCID Profile
0000-0003-0342-9024
Current Organisations
Universita degli Studi di Padova
,
The University of Texas at Austin
,
Harvard University
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Publisher: Springer Science and Business Media LLC
Date: 23-04-2005
Publisher: The Royal Society
Date: 16-02-2006
Abstract: It is well established that changes to the chemical environment can impair development, physiology and reproductive biology by contrast, impacts on communication have not been widely reported. This is surprising given that chemical communication is the most widely used sensory modality in nature, and that variation in the chemical composition of the environment is the rule, not the exception. Here, we show that chemically mediated species recognition in a swordtail fish, Xiphophorus birchmanni , can be hindered by anthropogenic disturbance to the signalling environment. Females have a strong preference for conspecific male chemical cues, yet they hybridize in nature with the congener X. malinche . Wild-caught females showed a strong preference for conspecifics when tested in clean water, but failed to show a preference when tested in stream water subject to sewage effluent and agricultural runoff. We hypothesized that this was due to the interaction between chemical communication systems and humic acid (HA), a ubiquitous, natural product elevated to high levels by anthropogenic processes. When exposed to elevated concentrations of HA, female X. birchmanni again lost their preference for conspecific male chemical cues, while visual mating preferences and motivation to mate were retained. Sub-lethal concentrations of seemingly benign substances can thus have a drastic effect on natural populations through their specific impact on communication systems.
Publisher: University of Chicago Press
Date: 2006
DOI: 10.1086/498278
Abstract: Studies of mate choice evolution tend to focus on how female mating preferences are acquired and how they select for greater elaboration of male traits. By contrast, far less is known about how female preferences might be lost or reversed. In swordtail fish Xiphophorus, female preference for the sword ornament is an ancestral trait. Xiphophorus birchmanni, however, is one species that has secondarily lost the sword. Using synthetic animation playback of "virtual" males, we found that female X. birchmanni preferred a swordless conspecific over a sworded heterospecific. Moreover, when offered the choice between a conspecific without a sword and one with a digitally attached sword, females preferred the former. These results suggest female preferences need not always select for elaboration of male traits, and they provide a plausible explanation for the lack of introgression of a sexual trait in a naturally occurring hybrid zone.
Publisher: Wiley
Date: 02-2005
Publisher: Brill
Date: 2007
DOI: 10.1163/156853907782418196
Abstract: Little is known about the mechanisms in iduals might use to compare group sizes when making decisions about group membership. One possibility is that animals use ratio to determine differences in group sizes. Weber's Law states that the ease of any numerical comparison is based on the ratio between the stimuli compared as the ratio becomes smaller the comparison becomes more difficult. We set out to test this prediction by offering female green swordtails, Xiphophorus helleri, dichotomous choices between different shoal sizes, varying both in ratios and absolute numbers of fish. Swordtails attended to the ratio of group size between stimulus shoals, rather than the numerical difference between shoals, when making shoaling decisions. Where group size ratio was 2:1, subjects showed a significant preference for the larger shoal, independent of the numerical difference between the shoals. When the ratio was 1.5:1, subjects showed no preference. The ratio between group sizes may, thus, be an important factor in shoaling decisions. More broadly, ratio could prove to be a widespread mechanism for animals to make numerical comparisons in group assessments.
Publisher: Oxford University Press (OUP)
Date: 18-05-2005
Publisher: Springer Science and Business Media LLC
Date: 05-09-2014
No related grants have been discovered for Gil Rosenthal.