Male–female morph interactions in the damselfly Nehalennia irene (Hagen)

1997 ◽  
Vol 75 (2) ◽  
pp. 253-260 ◽  
Author(s):  
Mark R. Forbes ◽  
Gina Schalk ◽  
J. Greg Miller ◽  
Jean M. L. Richardson
Keyword(s):  
Sexual Aggression ◽  
Indirect Evidence ◽  
Costs And Benefits ◽  
Conspecific Male ◽  
Mate Searching ◽  
Designed Experiments ◽  
Differential Costs ◽  
Nehalennia Irene ◽  
Differential Attraction ◽  
Female Morph

Several hypotheses concerning factors that favour coexistence of female morphs in damselflies (Zygoptera: Odonata) invoke differential attraction to (or harassment of) female morphs from mate-searching males. We designed experiments to determine whether males were differentially attracted to either of two discrete female morphs in a damselfly, Nehalennia irene (Hagen). One female morph was similar in colour and pattern to the conspecific male ("androchrome") and the other was dissimilar ("gynochrome"). Males were indiscriminate in their mating attempts. Overall, males were more attracted to gynochrome females; however, males that showed high response intensity to model males were equally likely to grasp models of the gynochrome and androchrome females. During male–female encounters in the field, androchrome females were more likely to chase males, whereas gynochrome females showed more refusal displays. Other direct and indirect evidence suggests that gynochrome females may be greater targets of sexual aggression than androchrome females while at the pond's edge, but that androchrome females more often frequent the pond's edge. Whether or not these differences in behaviour translate into differential costs and benefits of being a particular morph is unknown.

Female-limited polymorphism in a widespread damselfly: morph frequencies, male density, and phenotypic similarity of andromorphs to males

2008 ◽  
Vol 86 (10) ◽  
pp. 1131-1138 ◽  
Author(s):  
H. Van Gossum ◽  
T. Robb ◽  
M. R. Forbes ◽  
L. Rasmussen
Keyword(s):  
Animal Species ◽  
Conspecific Male ◽  
Male Harassment ◽  
Phenotypic Similarity ◽  
Male Density ◽  
Male Phenotype ◽  
Nehalennia Irene ◽  
Density Dependent Selection ◽  
Morph Frequency ◽  
Female Morph

In several animal species, one male type coexists with two to several female types, a polymorphism often explained in the context of sexual selection. Where it occurs, one female morph typically resembles the conspecific male phenotype, but the degree of resemblance varies across species. Here, we question whether the degree of phenotypic similarity between male-like females and males varies within species. Phenotypic resemblance is hypothesized to depend on the potential for frequency- and density-dependent selection on male and (or) female phenotypes. We studied six populations of the damselfly Nehalennia irene (Hagen, 1861) that differed widely in estimates of morph frequency and male density. Male-like females resemble males more than another female type resembles males, across populations, when comparisons are based on abdominal patterns. Abdomen phenotype does matter in male–female interactions of damselflies. Furthermore, male-like females were more similar to males at low and high density sites compared with sites with intermediate densities, contrary to the hypothesis that the potential for male harassment influences the degree of phenotypic similarity. Additionally, male-like females of most populations converged on the abdominal phenotype of males of one population rather than on that of syntopic males; a problem that has not received any attention.

scholarly journals When cooperation begets cooperation: the role of key individuals in galvanizing support

2015 ◽  
Vol 370 (1683) ◽  
pp. 20150012 ◽  
Author(s):  
Katherine McAuliffe ◽  
Richard Wrangham ◽  
Luke Glowacki ◽  
Andrew F. Russell
Keyword(s):  
Cooperative Breeding ◽  
Conflicts Of Interest ◽  
Costs And Benefits ◽  
Case Study Approach ◽  
Response Strategies ◽  
Study Approach ◽  
Limited Power ◽  
Differential Costs

Life abounds with examples of conspecifics actively cooperating to a common end, despite conflicts of interest being expected concerning how much each individual should contribute. Mathematical models typically find that such conflict can be resolved by partial-response strategies, leading investors to contribute relatively equitably. Using a case study approach, we show that such model expectations can be contradicted in at least four disparate contexts: (i) bi-parental care; (ii) cooperative breeding; (iii) cooperative hunting; and (iv) human cooperation. We highlight that: (a) marked variation in contributions is commonplace; and (b) individuals can often respond positively rather than negatively to the contributions of others. Existing models have surprisingly limited power in explaining these phenomena. Here, we propose that, although among-individual variation in cooperative contributions will be influenced by differential costs and benefits, there is likely to be a strong genetic or epigenetic component. We then suggest that selection can maintain high investors ( key individuals ) when their contributions promote support by increasing the benefits and/or reducing the costs for others. Our intentions are to raise awareness in—and provide testable hypotheses of—two of the most poorly understood, yet integral, questions regarding cooperative ventures: why do individuals vary in their contributions and when does cooperation beget cooperation?

Multi-annual variation in female morph frequencies of the polymorphic damselfly, Nehalennia irene, at continental and regional scales

2009 ◽  
Vol 59 (3) ◽  
pp. 313-326 ◽  
Author(s):  
Janice Ting ◽  
Thomas Sherratt ◽  
Jessica Bots ◽  
Felipe Pérez Jvostov ◽  
Arne Iserbyt ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Annual Variation ◽  
Regional Scale ◽  
Operational Sex Ratio ◽  
Male Harassment ◽  
Continental Scale ◽  
Male Density ◽  
Nehalennia Irene ◽  
Morph Frequency ◽  
Female Morph

AbstractFemale-limited polymorphism occurs in different animal taxa but is particularly abundant among species of damselflies (Insecta: Odonata), most likely as a consequence of selection to avoid excessive male harassment. Recent work on the damselfly Nehalennia irene indicated that within year spatial variation in female morph frequencies was limited in nearby populations (i.e. intra-regional scale), but large at a continental scale. As anticipated, some of the observed variation in morph frequency was correlated with variation in the estimated degree of male harassment towards female morphs, measured by male density and operational sex ratio. Here, we extended earlier work by quantifying variation in morph frequency over two to three years, allowing us to elucidate how morph frequencies vary temporally at both intra-regional and continental scales (data for 8 populations over three years and for 33 populations over two years, respectively). Annual variation in morph frequencies was relatively high at the intra-regional scale, but was never large enough to obscure the underlying spatial pattern at the continental scale. At both geographic scales, male density and operational sex ratio were highly variable between years. The estimated degree of male harassment correlated with variation in morph frequency within some regions, but not all. Together, the observed natural variation in female morph frequencies may be partly explained by variation in male harassment, but it appears that a complete understanding will require considering the role of other environmental factors.

Using the research on intergroup conflict in nonhuman animals to help inform patterns of human intergroup conflict

2019 ◽  
Vol 42 ◽  
Author(s):  
Amanda R. Ridley ◽  
Melanie O. Mirville
Keyword(s):  
Large Body ◽  
Nonhuman Animal ◽  
Intergroup Conflict ◽  
Costs And Benefits ◽  
Animal Groups ◽  
Interesting Article ◽  
Nonhuman Animals

Abstract There is a large body of research on conflict in nonhuman animal groups that measures the costs and benefits of intergroup conflict, and we suggest that much of this evidence is missing from De Dreu and Gross's interesting article. It is a shame this work has been missed, because it provides evidence for interesting ideas put forward in the article.

Efficacy of Crisis Intervention

Crisis ◽  
1999 ◽  
Vol 20 (2) ◽  
pp. 78-85 ◽  
Author(s):  
Thomas Reisch ◽  
Petra Schlatter ◽  
Wolfgang Tschacher
Keyword(s):  
Crisis Intervention ◽  
Intervention Program ◽  
Suicide Ideation ◽  
Indirect Evidence ◽  
Well Being ◽  
Term Therapy ◽  
Contributing Factors ◽  
Step Therapy ◽  
Long Term Therapy ◽  
The Impact

This study assesses the efficacy of the treatment approach implemented in the Bern Crisis Intervention Program, where particular emphasis is placed on the remediation of suicide ideation and suicidal behavior, and depression, fear, and phobia are generally considered to be contributing factors. Four questionnaires addressing psychopathology, emotional well-being, social anxiety, and personality were administered prior to and after the treatment of 51 patients over a period of 2 to 3 weeks. The reduction of symptoms contributing to suicidal ideation and behavior was interpreted as indirect evidence of an antisuicidal effect of the program. Significant improvements were found in the psychopathology ratings, with depression and anxiety showing the largest reductions. The impact on personality and social phobia, however, was only moderate, and on average patients still exhibited symptoms after attending the program. This residual symptomatology points to the necessity of introducing a two-step therapy approach of intensive intervention targeted at the precipitating causes of the crisis, augmented by long-term therapy to treat underlying problems.

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