Sexual dimorphism in trophic morphology and feeding behavior of wolf spiders (Araneae: Lycosidae) as a result of differences in reproductive roles

2002 ◽  
Vol 80 (4) ◽  
pp. 679-688 ◽  
Author(s):  
Sean E Walker ◽  
Ann L Rypstra
Keyword(s):  
Sexual Dimorphism ◽  
Feeding Behavior ◽  
Wolf Spider ◽  
Foraging Success ◽  
Wolf Spiders ◽  
Niche Divergence ◽  
Trophic Morphology ◽  
Males And Females ◽  
Almost All ◽  
The Relationship

Sexual dimorphism in animals is thought to be a result of differences between the sexes in the relationship between reproductive success and a trait, or a result of intersexual niche divergence. Intersexual niche divergence occurs as a result of competition between the sexes and is generally inferred from sexual dimorphism in morphological features associated with feeding. However, differences between the sexes in trophic morphology can be a result of either intersexual niche divergence or differences in the relationship between foraging success and reproduction between the sexes. In this study we examined sex differences in the trophic morphology of six wolf spider species and in the feeding behavior of two of these species. Females were larger than males in almost all characteristics even after differences in body size were accounted for, and killed and consumed more prey. We found little evidence of intersexual niche divergence based on differences in the relative prey sizes preferred by males and females of two species. Our data suggest that differences in the reproductive roles of males and females have resulted in foraging success being more important for female fitness than for male fitness and that differences in reproductive roles can result in sexual dimorphism.

Locomotion in Burrowing and Vagrant Wolf Spiders (Lycosidae)

1981 ◽  
Vol 92 (1) ◽  
pp. 305-321 ◽  
Author(s):  
T. M. WARD ◽  
W. F. HUMPHREYS
Keyword(s):  
Wolf Spider ◽  
The Body ◽  
Power Stroke ◽  
Phase Lag ◽  
Running Speed ◽  
Wolf Spiders ◽  
High Speeds ◽  
Phase Lags ◽  
The Relationship

Locomotion in the vagrant wolf spider Trochosa ruricola is compared to that in the burrow dwelling wolf spider Lycosa tarentula (Araneae: Lycosidae). L. tarentula takes relatively shorter steps than T. ruricola. At high speeds T. ruricola approximates an alternating tetrapod gait but this does not occur in L. tarentula. Phase lag differs between species and varies marginally with speed except for ipsilateral phase lags in L. tarentula which are erratic if they include leg 1. In both species the protraction/retraction ratio is directly related to both running speed and stepping frequency, but the relationship is more marked in L. tarentula. The protraction/retraction ratio is more variable in leg 1 and varies between legs along the body but by a greater amount in L. tarentula. In these spiders, in contrast to the situation in many insects, both the duration of protraction and retraction show marked inverse relationships to stepping frequency. The power stroke (retraction) occupies a variable proportion of the stepping cycle, which is not the case in other spiders, and this proportion is lower than for other spiders. It is suggested that the first pair of legs is used more for sensory than for locomotory purpose and that this is more marked in the burrow dwelling species, L. tarentula.

scholarly journals SEXUAL DIMORPHISM IN PSEUDOPUS APODUS (REPTILIA: SAURIA: ANGUIDAE) FROM THE STEPPE CRIMEA

2018 ◽  
Vol 19 ◽  
pp. 1-21
Author(s):  
Oleg V. Kukushkin ◽  
Igor V. Dovgal
Keyword(s):  
Sexual Dimorphism ◽  
Morphometric Parameters ◽  
The Body ◽  
Body Proportions ◽  
Reliable Determination ◽  
Kerch Peninsula ◽  
The Crimea ◽  
Males And Females ◽  
Almost All

The current paper is focused on sexual dimorphism of a giant glass lizard, or sheltopusik, Pseudopus apodus apodus (Pallas, 1775) from its northernmost populations inhabiting the Crimea. In total, 72 P. apodus individuals (45 males and 27 females) were collected at the Kerch Peninsula during 2013–2017. To estimate the variability, 13 morphometric parameters and 18 indices characterizing the head and body proportions were used. It was found that males and females differed significantly by means of almost all parameters, except the body and tail sizes. Besides that, the differences by 10 ratios characterizing head proportions were revealed as well. However, a reliable determination of the lizard sex using linear sizes and/or ratios values seems to be impossible because of the strong overlap of the variability ranges in both sexes. At the same time, the use of the canonical discriminant analysis by the complex of morphometric parameters and by ratios has shown that the males and females in both datasets are classified correctly basing on the sex with an accuracy approximating 100%. The differences in the allometric growth of males and females partially define the sexual dimorphism of P. apodus on head size and shape. A sex-related differences in the development of at least one pair of parameters (head and snout lengths) were clearly evident, since isometry was established for males, while allometry ‒ for females. Moreover, the systems of correlation between the body and head parts differ in both sexes. Thus, male characterisitics correlate significanly, while the female ones were less toughly connected, and some pairs of parameters did not correlate at all.

scholarly journals Relative growth of freshwater prawn Macrobrachium brasiliense (Decapoda, Palaemonidae) and its implications for reproduction

2019 ◽  
Vol 109 ◽  
Author(s):  
Caio dos Santos Nogueira ◽  
Marcela Silvano de Oliveira ◽  
Giuliano Buzá Jacobucci ◽  
Ariádine Cristine de Almeida
Keyword(s):  
Sexual Dimorphism ◽  
Sexual Maturity ◽  
Carapace Length ◽  
Freshwater Prawn ◽  
Relative Growth ◽  
Guarding Behavior ◽  
Males And Females ◽  
One Year ◽  
Almost All

ABSTRACT The main objective of this study was to estimate the morphological sexual maturity of Macrobrachium brasiliense (Heller, 1862) and to analyze the relative growth of the species. During one year of sampling, from July 2012 to June 2013, 199 specimens were collected in a stream located in a Cerrado biome, in the Triângulo Mineiro region, state of Minas Gerais. Once identified and sexed, the length of the carapace, the length of the segments of the chelipeds (ischium, merus, carpus, propodus and dactyl) and width of the pleura were measured (mm). The maximum and mean sizes of the carapace length measured 20.5 mm (Mean: 9.6 ± 4.2 mm) and 20.1 mm (Mean: 7.7 ± 3.4 mm) for males and females, respectively. The propodus length for males, and the pleura width for females, were used for the classification of the specimens into juvenile and adult, using K-means analysis and discriminant analysis. The relative growth of the species was also evaluated through covariance analysis for all structures (ANCOVA, α = 0.05). In females, the growth of most structures occurred equally between juveniles and adults, with the exception of the merus and pleura structures. On the other hand, the growth of almost all structures of males differed between juveniles and adults. Only the carpus and the pleura growth were similar. We also estimated the size at onset of morphological sexual maturity at 8.64 mm CL for males (CL50% r = 1.71) and 8.03 mm CL for females (CL50% r = 0.07). Our results contribute to the understanding of some important questions related to the reproductive biology of M. brasiliense. We noted that males grow differently from females and become the largest individuals in the population, resulting in a sexual dimorphism. Such sexual dimorphism might promote the development of the temporary mating guarding behavior, a reproductive strategy very important for caridean shrimps.

Importance of body size and hunting strategy during interactions between the Mexican red-rump tarantula (Brachypelma vagans) and the wolf spider Lycosa subfusca

2013 ◽  
Vol 91 (8) ◽  
pp. 545-553 ◽  
Author(s):  
A. Dor ◽  
Y. Hénaut
Keyword(s):  
Life History ◽  
Wolf Spider ◽  
Life Stages ◽  
Wolf Spiders ◽  
Predatory Behaviour ◽  
Spider Species ◽  
Behavioural Adaptation ◽  
Brachypelma Vagans ◽  
The Relationship ◽  
Hunting Strategy

Behavioural adaptation helps animals to maximize their ability to obtain food and to avoid being eaten, increasing fitness. To achieve this, they must assess predation risk and evaluate foraging needs simultaneously. In two sympatric spider species, the wandering wolf spider Lycosa subfusca F.O.P. Cambridge, 1902 and the sit-and-wait Mexican red-rump tarantula (Brachypelma vagans Ausserer, 1875), we studied the relationship between predatory behaviour and antipredatory behaviour at different life stages. In the laboratory, encounters were organized between one wolf spider (small, medium-sized, or large) and one tarantula (spiderling, small, medium-sized, or large). Attack latencies and behaviours were recorded. The results showed that wolf spiders attacked and successfully captured younger tarantulas, while they avoided or retreated from older ones. Tarantulas preferentially attacked and captured older wolf spiders. On other hand, younger wolf spiders were more cautious than older ones, which waited until for the tarantulas to attack before retreating. Younger tarantulas were also more cautious than adults, which never retreated from attack and increased their success in attacks with age. Finally, we discuss the relationship between the predatory strategies of both spiders with their perception abilities and life history.

Intersexual niche divergence in northern map turtles (Graptemys geographica): the roles of diet and habitat

2008 ◽  
Vol 86 (11) ◽  
pp. 1235-1243 ◽  
Author(s):  
G. Bulté ◽  
M.-A. Gravel ◽  
G. Blouin-Demers
Keyword(s):  
Sexual Dimorphism ◽  
Habitat Use ◽  
Prey Selection ◽  
Isotope Analysis ◽  
Prey Distribution ◽  
Trophic Morphology ◽  
Males And Females ◽  
Map Turtles ◽  
Graptemys Geographica ◽  
Intersexual Competition

Sexual dimorphism in body size and in trophic morphology are common in animals and are often concordant with patterns of habitat use and diet. Proximate factors leading to intersexual differences in habitat use, however, are challenging to unravel because these differences may stem from sexual dimorphism or may be caused by intersexual competition. Intersexual differences in diet and habitat use are common in size dimorphic reptiles. In this study, we investigated factors contributing to intersexual differences in diet and habitat use in a population of northern map turtles ( Graptemys geographica (Le Sueur, 1817)) from Ontario, Canada. Using radiotelemetry, we showed that in a lake map turtles do not exhibit intersexual differences in habitat use, in contrast to river populations. Patterns of habitat use were also inconsistent with prey distribution. The lack of intersexual habitat use differences in our lake population, despite marked differences in prey distribution, also indicated that intersexual habitat use differences documented in river populations are a consequence of sexual dimorphism in swimming capacity. Using stable isotope analysis and fecal analysis, we found a large dietary overlap between males and females, indicating no intersexual competition for food. Patterns of prey selection in females, however, were concordant with the reproductive role hypothesis.

scholarly journals Lost lovers linked at long last: elusive female Nanophyllium mystery solved after a century of being placed in a different genus (Phasmatodea, Phylliidae)

ZooKeys ◽  
2020 ◽  
Vol 969 ◽  
pp. 43-84 ◽  
Author(s):  
Royce T. Cumming ◽  
Stephane Le Tirant ◽  
Sierra N. Teemsma ◽  
Frank H. Hennemann ◽  
Luc Willemse ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Papua New Guinea ◽  
Small Body ◽  
Species Group ◽  
Laboratory Rearing ◽  
Males And Females ◽  
The Many ◽  
Relationship Of ◽  
The Relationship ◽  
Captive Rearing

After successful laboratory rearing of both males and females from a single clutch of eggs, the genus Nanophyllium Redtenbacher, 1906 (described only from males) and the frondosum species group within Phyllium (Pulchriphyllium) Griffini, 1898 (described only from females) are found to be the opposite sexes of the same genus. This rearing observation finally elucidates the relationship of these two small body sized leaf insect groups which, for more than a century, have never been linked before. This paper synonymizes the frondosum species group with Nanophyllium Redtenbacher, 1906 in order to create a singular and clearly defined taxonomic group. Five species are transferred from the Phyllium (Pulchriphyllium) frondosum species group and create the following new combinations: Nanophyllium asekiense (Größer, 2002), comb. nov.; Nanophyllium chitoniscoides (Größer, 1992), comb. nov.; Nanophyllium frondosum (Redtenbacher, 1906), comb. nov.; Nanophyllium keyicum (Karny, 1914), comb. nov.; Nanophyllium suzukii (Größer, 2008), comb. nov. The only taxon from this species group not transferred from the frondosum species group to Nanophyllium is Phyllium (Pulchriphyllium) groesseri Zompro, 1998. Based on protibial exterior lobes, this species belongs in the schultzei species group as described in Hennemann et al. 2009 and is therefore excluded from further discussion here. The rearing of Nanophyllium also yielded the male Nanophyllium asekiense (Größer, 2002), comb. nov. thus, enabling comparison of this male to the other previously known Nanophyllium species. Two new species of nano-leaf insects are described within, Nanophyllium miyashitaisp. nov., from Morobe Province, Papua New Guinea, and Nanophyllium daphnesp. nov., from Biak Island, Papua Province, Indonesia. With such distinct sexual dimorphism in Nanophyllium between sexes, which have only now been matched up via captive rearing, illustrated within are numerous specimens which might represent the unknown opposite sexes of the many currently known species of Nanophyllium. Due to pronounced sexual dimorphism in Nanophyllium, only future captive rearing or molecular analysis will match up the many unknown sexes. To conclude, with the description of two new Nanophyllium species, dichotomous keys to species for known males and females are presented.

Attachment and Field Dependence: Individual Differences in Information Processing

2004 ◽  
Vol 9 (1) ◽  
pp. 43-55 ◽  
Author(s):  
Patrizia Vermigli ◽  
Alessandro Toni
Keyword(s):  
Information Processing ◽  
Individual Differences ◽  
Field Dependence ◽  
Attachment Styles ◽  
Close Relationships ◽  
Adult Age ◽  
Males And Females ◽  
Figure Test ◽  
The Relationship ◽  
Measure Field

The present research analyzes the relationship between attachment styles at an adult age and field dependence in order to identify possible individual differences in information processing. The “Experience in Close Relationships” test of Brennan et al. was administered to a sample of 380 individuals (160 males, 220 females), while a subsample of 122 subjects was given the Embedded Figure Test to measure field dependence. Confirming the starting hypothesis, the results have shown that individuals with different attachment styles have a different way of perceiving the figure against the background. Ambivalent and avoidant individuals lie at the two extremes of the same dimension while secure individuals occupy the central part. Significant differences also emerged between males and females.

Observation on the breeding biology of Polypedates teraiensis (Dubois, 1987) (Amphibia: Rhacophoridae)

2017 ◽  
Vol 17 (1) ◽  
pp. 25-32
Author(s):  
Jacinta Lalchhanhimi ◽  
Lalremsanga H.T.
Keyword(s):  
Sexual Dimorphism ◽  
Breeding Season ◽  
Sound Production ◽  
Reproductive Function ◽  
Breeding Biology ◽  
Tree Frog ◽  
University Campus ◽  
Morphometric Measurements ◽  
Advertisement Calls ◽  
Males And Females

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.

Contemporary Qur'anic Studies in Iran and its Relationship with Qur'anic Studies in the West

2012 ◽  
Vol 14 (1) ◽  
pp. 45-72
Author(s):  
Morteza Karimi-Nia
Keyword(s):  
Islamic Law ◽  
Human Sciences ◽  
The West ◽  
Communications Technologies ◽  
Religious Learning ◽  
The Status ◽  
Islamic Republic Of Iran ◽  
Almost All ◽  
The Impact ◽  
The Relationship

The status of tafsīr and Qur'anic studies in the Islamic Republic of Iran has changed significantly during recent decades. The essay provides an overview of the state of Qur'anic studies in Iran today, aiming to examine the extent of the impact of studies by Western scholars on Iranian academic circles during the last three decades and the relationship between them. As in most Islamic countries, the major bulk of academic activity in Iran in this field used to be undertaken by the traditional ʿulamāʾ; however, since the beginning of the twentieth century and the establishment of universities and other academic institutions in the Islamic world, there has been increasing diversity and development. After the Islamic Revolution, many gradual changes in the structure and approach of centres of religious learning and universities have occurred. Contemporary advancements in modern sciences and communications technologies have gradually brought the institutions engaged in the study of human sciences to confront the new context. As a result, the traditional Shīʿī centres of learning, which until 50 years ago devoted themselves exclusively to the study of Islamic law and jurisprudence, today pay attention to the teaching of foreign languages, Qur'anic sciences and exegesis, including Western studies about the Qur'an, to a certain extent, and recognise the importance of almost all of the human sciences of the West.

Sexual Dimorphism among the Kathmandu University Students Assessed by Anthropometric Studies

2018 ◽  
Vol 9 (05) ◽  
pp. 20469-20472
Author(s):  
Shakya R ◽  
Bhattacharya SC ◽  
Shrestha R
Keyword(s):  
Young Adults ◽  
Sexual Dimorphism ◽  
Young Adult ◽  
University Students ◽  
Plastic Surgery ◽  
Age Group ◽  
Adult Age ◽  
Clinically Normal ◽  
Crime Detection ◽  
Males And Females

Objectives: To observe the sexual dimorphism among the young adult age group ranging from 18-21 years, of Kathmandu University students by measuring craniofacial circumference and canthal distances. Rationale of the study: These data could be useful for establishing the craniofacial standards and adds an implementation on plastic surgery, crime detection as well as in the industrial field. Method: 300 clinically normal students of Kathmandu University aged between 18-21 years were examined for the study. Fronto-occipital circumference, outer and inner canthal distances were measured. All the parameters were compared between males and females. Result: The cranial circumference as well as the inner and outer canthal distance in males was found to be significantly higher as compared to the females. Conclusion: The results concluded that sexual dimorphism remarkably exists in young adults of Kathmandu University students.

Sign in / Sign up

Export Citation Format

Share Document