scholarly journals Latitudinal gradients in sexual dimorphism: Alternative hypotheses for variation in male traits

2021 ◽  
Author(s):  
Christopher M. Murray ◽  
Caleb D. McMahan ◽  
Allison R. Litmer ◽  
Jeffrey M. Goessling ◽  
Dustin Siegel
2010 ◽  
Vol 278 (1713) ◽  
pp. 1777-1785 ◽  
Author(s):  
Sean P. Mullen ◽  
Wesley K. Savage ◽  
Niklas Wahlberg ◽  
Keith R. Willmott

Latitudinal gradients in species richness are among the most well-known biogeographic patterns in nature, and yet there remains much debate and little consensus over the ecological and evolutionary causes of these gradients. Here, we evaluated whether two prominent alternative hypotheses (namely differences in diversification rate or clade age) could account for the latitudinal diversity gradient in one of the most speciose neotropical butterfly genera ( Adelpha ) and its close relatives. We generated a multilocus phylogeny of a diverse group of butterflies in the containing tribe Limenitidini, which has both temperate and tropical representatives. Our results suggest there is no relationship between clade age and species richness that could account for the diversity gradient, but that instead it could be explained by a significantly higher diversification rate within the predominantly tropical genus Adelpha . An apparent early larval host-plant shift to Rubiaceae and other plant families suggests that the availability of new potential host plants probably contributed to an increase in diversification of Adelpha in the lowland Neotropics. Collectively, our results support the hypothesis that the equatorial peak in species richness observed within Adelpha is the result of increased diversification rate in the last 10–15 Myr rather than a function of clade age, perhaps reflecting adaptive divergence in response to the dramatic host-plant diversity found within neotropical ecosystems.


2009 ◽  
Vol 156 (9) ◽  
pp. 1917-1928 ◽  
Author(s):  
Alvar Carranza ◽  
Omar Defeo ◽  
Juan Carlos Castilla ◽  
Thiago Fernando L. V. B. Rangel

2006 ◽  
Vol 20 (2) ◽  
pp. 79-93 ◽  
Author(s):  
R.C. Howard ◽  
A. Chaiwutikornwanich

This study combined an individual differences approach to interrogative suggestibility (IS) with ERP recordings to examine two alternative hypotheses regarding the source of individual differences in IS: (1) differences in attention to task-relevant vis-à-vis task-irrelevant stimuli, and (2) differences in one or more memory processes, indexed by ERP old/new effects. Sixty-five female participants underwent an ERP recording during the 50 min interval between immediate and delayed recall of a short story. ERPs elicited by pictures that either related to the story (“old”), or did not relate to the story (“new”), were recorded using a three-stimulus visual oddball paradigm. ERP old/new effects were examined at selected scalp regions of interest at three post-stimulus intervals: early (250-350 ms), middle (350-700 ms), and late (700-1100 ms). In addition, attention-related ERP components (N1, P2, N2, and P3) evoked by story-relevant pictures, story-irrelevant pictures, and irrelevant distractors were measured from midline electrodes. Late (700-1100 ms) frontal ERP old/new differences reflected individual differences in IS, while early (250-350 ms) and middle latency (350-700 ms) ERP old/new differences distinguished good from poor performers in memory and oddball tasks, respectively. Differences in IS were not reflected in ERP indices of attention. Results supported an account of IS as reflecting individual differences in postretrieval memory processes.


Author(s):  
I. R. Khuzina ◽  
V. N. Komarov

The paper considers a point of view, based on the conception of the broad understanding of taxons. According to this point of view, rhyncholites of the subgenus Dentatobeccus and Microbeccus are accepted to be synonymous with the genus Rhynchoteuthis, and subgenus Romanovichella is considered to be synonymous with the genus Palaeoteuthis. The criteria, exercising influence on the different approaches to the classification of rhyncholites, have been analyzed (such as age and individual variability, sexual dimorphism, pathological and teratological features, degree of disintegration of material), underestimation of which can lead to inaccuracy. Divestment of the subgenuses Dentatobeccus, Microbeccus and Romanovichella, possessing very bright morphological characteristics, to have an independent status and denomination to their synonyms, has been noted to be unjustified. An artificial system (any suggested variant) with all its minuses is a single probable system for rhyncholites. The main criteria, minimizing its negative sides and proving the separation of the new taxon, is an available mass-scale material. The narrow understanding of the genus, used in sensible limits, has been underlined to simplify the problem of the passing the view about the genus to the other investigators and recognition of rhyncholites for the practical tasks.


2017 ◽  
Vol 17 (1) ◽  
pp. 25-32
Author(s):  
Jacinta Lalchhanhimi ◽  
Lalremsanga H.T.

The breeding biology of tree frog, Polypedates teraiensis was studied during the breeding season at Mizoram University Campus. It was found that sound production by male during the breeding season was primarily a reproductive function and advertisement calls attract females to the breeding areas and announce other males that a given territory is occupied. The aim of this study was to provide the detailed information on the breeding behaviour and the advertisement calls of Polypedates teraiensis. The morphometric measurements of the amplecting pairs (males and females) for sexual dimorphism along with clutch sizes were also studied.


2019 ◽  
Author(s):  
Marcia Hiriart ◽  
Myrian Velasco ◽  
Marcia Hiriart

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