Thelytokous Parthenogenesis and Dominance Hierarchies in the Ponerine Ant, Platythyrea punctata

1995 ◽  
Vol 82 (1) ◽  
pp. 40-41 ◽  
Author(s):  
J. Heinze ◽  
B. H�lldobler
Keyword(s):  
Thelytokous Parthenogenesis ◽  
Dominance Hierarchies ◽  
Ponerine Ant ◽  
Platythyrea Punctata

Hybridogenesis through thelytokous parthenogenesis in two C ataglyphis desert ants

2012 ◽  
Vol 22 (4) ◽  
pp. 947-955 ◽  
Author(s):  
P. A. Eyer ◽  
L. Leniaud ◽  
H. Darras ◽  
S. Aron
Keyword(s):  
Thelytokous Parthenogenesis ◽  
Desert Ants

Thelytokous Parthenogenesis in Eusocial Hymenoptera

2013 ◽  
Vol 58 (1) ◽  
pp. 273-292 ◽  
Author(s):  
Christian Rabeling ◽  
Daniel J.C. Kronauer
Keyword(s):  
Thelytokous Parthenogenesis

scholarly journals Understanding testosterone variation in a tropical lek-breeding bird

2011 ◽  
Vol 7 (4) ◽  
pp. 506-509 ◽  
Author(s):  
Thomas B. Ryder ◽  
Brent M. Horton ◽  
Ignacio T. Moore
Keyword(s):  
Social Status ◽  
Strong Predictor ◽  
Breeding Birds ◽  
Male Dominance ◽  
Surprising Result ◽  
Breeding Bird ◽  
Dominance Hierarchies ◽  
Testosterone Levels ◽  
Male Display ◽  
Pipra Filicauda

Male reproductive coalitions, in which males cooperate to attract females, are a rare strategy among vertebrates. While some studies have investigated ultimate aspects of these relationships, little is known about the mechanistic role that hormones play in modulating cooperative behaviours. Here, we examined male testosterone variation in a tropical lekking bird, the wire-tailed manakin ( Pipra filicauda ), which exhibits cooperative male–male display coalitions. We found that testosterone levels in territorial males were comparable to those of temperate breeding birds, a surprising result given their environmental, social and reproductive dynamics. In addition, social status rather than plumage was a strong predictor of testosterone variation. Territorial males had significantly higher testosterone levels than did two other plumage classes of floater males, who do not hold territories. We hypothesize that testosterone variation plays an important role in the establishment of male dominance hierarchies (competition), while concurrently facilitating stable display partnerships (cooperation).

How information about individual pigs can help to reduce aggression and injuries after mixing

1996 ◽  
Vol 1996 ◽  
pp. 12-12
Author(s):  
H.W. Erhard ◽  
M. Mendl ◽  
D.D. Ashley
Keyword(s):  
Negative Effects ◽  
Dominance Hierarchies ◽  
Low Levels ◽  
Pig Husbandry

Dominance hierarchies are commonly observed in groups of pigs (Beilharz & Cox 1967). These hierarchies appear to be established by individuals assessing each other's relative abilities, usually through fighting (Rushen & Pajor 1987). The resulting aggression is a well documented problem in pig husbandry. It could be reduced by mixing pigs who differ in certain respects, such that they rapidly form a hierarchy without vigorous fighting. Hessing et al. (1994) found that mixing pigs who showed high levels of resistance to being placed on their backs in a “back test” with pigs who were less resistant resulted in low levels of aggression. In this study we investigated whether mixing pigs which differ in their aggressiveness could reduce the negative effects of regrouping.

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