scholarly journals Evolutionary ecology of Datura stramonium: equal plant fitness benefits of growth and resistance against herbivory

2003 ◽  
Vol 16 (1) ◽  
pp. 127-137 ◽  
Author(s):  
P. L. Valverde ◽  
J. Fornoni ◽  
J. Nunez-Farfan
Author(s):  
Judith L. Bronstein

The unusual behavior of cleaner fish has attracted both popular and scientific curiosity since its discovery early in the 20th century. These fish apparently make their living by removing external parasites from “host” fishes of other species (some also remove bacteria or diseased and injured tissue). When they approach cleaners, hosts assume an unusual motionless posture that allows cleaners to feed from their scales, from their gill cavities, or even inside their mouths. For their trouble, cleaner fish get a meal, and hosts get a good cleaning. The interaction between cleaner fish and their hosts is generally classified as a mutualism, or mutually beneficial interaction between species. Stories about this and other mutualisms have become staples of nature documentaries and the popular literature and have helped lure many students into a lifetime of studying biology. From the perspective of evolutionary ecology, however, the cleaner-host relationship is anything but straightforward (Poulin and Grutter 1996). First, it is not at all clear that this interaction confers reciprocal fitness benefits. Despite several decades of effort, only one study has shown that cleaners significantly reduce hosts’ parasite loads (Grutter 1999), and none has yet demonstrated that reducing parasite loads increases host success. Since cleaners often gouge the host’s flesh, particularly when parasites are few, the interaction is often more costly than beneficial. Second, if cleaning does not confer an advantage, it is not evident why hosts should tolerate and even actively solicit cleaners’ attention. In fact, sometimes hosts lure cleaners only to eat them, but the conditions under which it might be beneficial for a host to doublecross its cleaners like this remain unexplored. Third, we don’t really understand how cleaning behaviors arose in the first place, considering that the first individuals that approached hosts to feed on parasites were very likely eaten. Despite this constraint, cleaning has apparently evolved multiple times; it is found in at least five families, in both marine and freshwater species, and in both the temperate zone and the tropics.


Cell ◽  
2016 ◽  
Vol 165 (2) ◽  
pp. 464-474 ◽  
Author(s):  
Kei Hiruma ◽  
Nina Gerlach ◽  
Soledad Sacristán ◽  
Ryohei Thomas Nakano ◽  
Stéphane Hacquard ◽  
...  

2020 ◽  
Author(s):  
Jaimie Krems ◽  
Keelah Williams ◽  
Laureon Allison Watson ◽  
Douglas Kenrick ◽  
Athena Aktipis

Friendships provide material benefits, bolster health, and may help solve adaptive challenges. However, a recurrent obstacle to sustaining those friendships—and thus enjoying many friendship-mediated fitness benefits—is interference from other people. Friendship jealousy may be well-designed for helping both men and women meet the recurrent, adaptive challenge of retaining friends in the face of such third-party interference. Although we thus expect several sex similarities in the general cognitive architecture of friendship jealousy (e.g., it is attuned to friend value), there are also sex differences in friendship structures and historical functions, which might influence the inputs of friendship jealousy (e.g., the value of any one friendship). If so, we should also expect some sex differences in friendship jealousy. Findings from a reanalysis of previously-published data and a new experiment, including both U.S. student and adult community participants (N = 993), provide initial support for three predicted sex differences: women (versus men) report greater friendship jealousy at the prospective loss of best friends to others, men (versus women) report greater friendship jealousy at the prospective loss of acquaintances to others, and men’s (but not women’s) friendship jealousy is enhanced in the context of intergroup contests.


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