scholarly journals Diet composition, body condition and sexual size dimorphism of the common African toad (Amietophrynus regularis) in urban and agricultural landscape

2021 ◽  
Author(s):  
Benjamin Yeboah Ofori ◽  
John Bosu Mensah ◽  
Roger Sigismund Anderson ◽  
Daniel Korley Attuquayefio
Keyword(s):  
Body Condition ◽  
Diet Composition ◽  
Sexual Size Dimorphism ◽  
Agricultural Landscape ◽  
Individual Characteristics ◽  
Generalist Predator ◽  
Natural Habitats ◽  
Size Dimorphism ◽  
The Common ◽  
Prey Items

AbstractLand use and land cover change (LULCC) are major drivers of global biodiversity loss. The conversion of natural habitats into human-modified landscapes poses novel and multifaceted environmental stressors to organisms, influencing their ecology, physiology, life history and fitness. Although the effects of LULCC have been studied extensively at the community level, there is scant information about its effect on population and individual characteristics. We assessed the diet composition, body condition, and sexual size dimorphism of the common African toad (Amietophrynus regularis) in urban and agricultural landscape. Diet composition was evaluated using gut content analysis, while body condition was measured using residual mass index. Overall, 935 prey items comprising six classes, at least 18 orders and 31 families were obtained from toads. This broad dietary niche suggested that Amietophrynus regularis is a generalist predator. The family Formicidae was the most consumed prey item, with a frequency of occurrence above 80% at both sites. We found no sex- or habitat-biased dietary partitioning in the toads. A statistically significant positive correlation existed between snout-vent-length (SVL) and diversity of prey items (Pearson’s correlation r = 0.999, p ≤ 0.0001) for toads from farmland, which also had better body conditions. The toads showed female-biased sexual size dimorphism, but males had longer tibio-fibula, radio-ulna, foot, and distal fore limbs. This study is probably the first to assess the diet composition, body condition and sexual size dimorphism of Amietophrynus regularis simultaneously. The ecological, evolutionary and conservation implications of our findings are discussed.

scholarly journals Sexual Size Dimorphism and Positive Assortative Mating in Alpine Choughs (Pyrrhocorax graculus)

The Auk ◽  
2001 ◽  
Vol 118 (2) ◽  
pp. 553-556 ◽  
Author(s):  
Anne Delestrade
Keyword(s):  
Sample Size ◽  
Assortative Mating ◽  
Body Condition ◽  
Sexual Size Dimorphism ◽  
Morphological Characters ◽  
Positive Trend ◽  
Tarsus Length ◽  
Size Dimorphism ◽  
Positive Assortative Mating ◽  
Larger Sample

Abstract The degree of sexual size dimorphism in a number of different morphological characters was examined in a social corvid, the Alpine Chough, using measurements taken on 178 males and 144 females. A small amount of size dimorphism appeared in all morphological characters, and weight was the most dimorphic character. To identify if Alpine Choughs mate assortatively, measurements of mates were compared in 76 pairs. A positive assortative mating was found on tarsus length, and a small positive trend is suggested between body condition of partners, but that needs to be confirmed with a larger sample size.

Pattern of sexual size dimorphism supports the inverse of Rensch’s rule in two frog species

2014 ◽  
Vol 64 (1) ◽  
pp. 87-95 ◽  
Author(s):  
Di Lu ◽  
Cai Quan Zhou ◽  
Lian Jun Zhao ◽  
Wen Bo Liao
Keyword(s):  
Body Size ◽  
Sexual Size Dimorphism ◽  
Rana Temporaria ◽  
Rensch’S Rule ◽  
Size Dimorphism ◽  
Rensch's Rule ◽  
Frog Species ◽  
Mean Size ◽  
The Common ◽  
Males And Females

Rensch’s rule describes that sexual size dimorphism (SSD) increases with body size (hyperallometry) when males are larger, and decreases with body size (hypoallometry) when males are smaller. In this paper, on the basis of mean adult body size resulting from 18 populations of the common frogRana temporariaand 24 populations of the Tibetan frogNanorana parkeri, we tested the consistency of allometric relationships between males and females with Rensch’s rule. Our results show that the variation in degree of female-biased SSD increased with increasing mean size at intraspecific levels in two species, which is consistent with the inverse of Rensch’s rule. Furthermore, we tested the hypothesis that the degree of SSD decreased with increasing altitudes. Inconsistent with the predications of our hypothesis, we found no relationships between the degree of SSD and altitude for the two species investigated. These findings suggest that females living in adverse climates in high altitudes cannot adjust their body size as plastically as males.

scholarly journals Body size, diet and endoparasites of the microhylid frog Chiasmocleis capixaba in an Atlantic Forest area of southern Bahia state, Brazil

2006 ◽  
Vol 66 (1a) ◽  
pp. 107-173 ◽  
Author(s):  
M. Van Sluys ◽  
G. M. Schittini ◽  
R. V. Marra ◽  
A. R. M. Azevedo ◽  
J. J. Vicente ◽  
...  
Keyword(s):  
Body Size ◽  
Heavy Rainfall ◽  
Diet Composition ◽  
Sexual Size Dimorphism ◽  
Single Species ◽  
Size Dimorphism ◽  
Intestinal Nematode ◽  
Southern Bahia ◽  
Single Night ◽  
Cosmocerca Ornata

We analyzed the diet composition, endoparasites and sexual size dimorphism of the microhylid frog Chiasmocleis capixaba (Microhylidae) from a "mussununga" habitat in the municipality of Nova Viçosa, southern Bahia state, Brazil. All the 119 specimens analyzed were collected in a single night of heavy rainfall. Females (mean snout-vent length = 15.7 + 3.0 mm) were significantly larger than males (mean snout-vent length = 13.2 + 2.1 mm), and specimens of both sexes were smaller than those of a conspecific population previously reported in Aracruz, state of Espírito Santo state. The diet of C. capixaba was dominated by mites, ants and collembolans. Seventy-nine frogs (66.4% of the total) were infected by helminths, all belonging to a single species, Cosmocerca ornata, an intestinal nematode parasite.

Feeding relationships between sympatric Afrotropical tree frogs (genus Hyperolius): The effects of predator body size and season

2004 ◽  
Vol 54 (3) ◽  
pp. 293-302 ◽  
Author(s):  
◽  
◽  
◽  
◽  
◽  
...  
Keyword(s):  
Interspecific Competition ◽  
Diet Composition ◽  
Sexual Size Dimorphism ◽  
Stomach Contents ◽  
The Other ◽  
Size Dimorphism ◽  
Frog Species ◽  
Tree Frogs ◽  
The One ◽  
Average Size

AbstractThe feeding relationships of four sympatric, ecologically nearly unknown, tree frogs of southern Nigeria (Hyperolius sylvaticus, H. guttulatus, H. fusciventris burtoni, and H. concolor) were studied during both the dry and the rainy seasons. Stomach contents were obtained by stomach flushing. The largest species were H. guttulatus and H. concolor, whereas the other two species were of smaller average size. A statistically significant sexual size dimorphism was observed in H. guttulatus, H. concolor, and H. sylvaticus (in all species the females were larger), but not in H. fusciventris. In all four species, the frequency of animals with empty stomachs was significantly lower during the rainy season than during the dry season. The four frog species were mainly arthropodeating: Araneidae and Blattoidea were preyed upon mainly by the two largest species, Acarina and Lepidoptera were taken mainly by the two smaller species, and Diptera and Formicoidea were eaten frequently by all species. The diet composition was similar between seasons in three of the four species, and H. guttulatus was the only species showing considerable diet variation between seasons. We concluded that 1) the intensity of interspecific competition should be particularly high between the two larger species on the one hand, and between the two smaller species on the other hand; and 2) the intensity of the interspecific competition should be relatively constant throughout the year.

scholarly journals Sexual Size Dimorphism and Body Condition in the Australasian Gannet

PLoS ONE ◽  
2015 ◽  
Vol 10 (12) ◽  
pp. e0142653 ◽  
Author(s):  
Lauren P. Angel ◽  
Melanie R. Wells ◽  
Marlenne A. Rodríguez-Malagón ◽  
Emma Tew ◽  
John R. Speakman ◽  
...  
Keyword(s):  
Body Condition ◽  
Sexual Size Dimorphism ◽  
Size Dimorphism

Eastern Garter Snakes (Thamnophis sirtalis) with proportionally larger heads are in better condition

2011 ◽  
Vol 32 (3) ◽  
pp. 424-427 ◽  
Author(s):  
Karen Elgee ◽  
Gabriel Blouin-Demers
Keyword(s):  
Body Size ◽  
Body Condition ◽  
Sexual Size Dimorphism ◽  
Head Size ◽  
Thamnophis Sirtalis ◽  
Garter Snakes ◽  
Size Dimorphism ◽  
Trophic Morphology ◽  
Large Head ◽  
The Relationship

AbstractWe investigated sexual size dimorphism and trophic morphology dimorphism in Eastern Garter Snakes (Thamnophis sirtalis) to test predictions derived from the reproductive role hypothesis. Our first objective was to examine whether structures involved in feeding (head and jaws) are more divergent than body size. Female T. sirtalis were larger than males and had proportionally larger heads. Our second objective was to look for an advantage of large head size by examining the relationship between body condition and head size. Body condition was positively correlated with relative head size in T. sirtalis for both sexes, in agreement with the reproductive role hypothesis.

scholarly journals Trophic Ecology of the Cuban Boa, Chilabothrus angulifer (Boidae)

2020 ◽  
Vol 27 (2) ◽  
pp. 169-200
Author(s):  
Tomás M. Rodríguez-Cabrera ◽  
Ernesto Morell Savall ◽  
Sheila Rodríguez-Machado ◽  
Javier Torres
Keyword(s):  
Trophic Ecology ◽  
Prey Species ◽  
Feeding Habits ◽  
Domestic Animals ◽  
Foraging Strategies ◽  
Generalist Predator ◽  
Ontogenetic Shift ◽  
Natural Habitats ◽  
Anthropogenic Habitats ◽  
Prey Items

The Cuban Boa (Chilabothrus angulifer) is a top terrestrial predator in Cuba. References to prey species consumed by this boa date to when the first Europeans arrived in the region more than 500 years ago. However, long-term studies on its trophic ecology do not exist. The scarce and scattered records on its feeding habits indicate that this boa preys on a variety of native and domestic animals. Based on dietary information collected in the field and from the literature, we characterized the diet of this snake and tested four different hypotheses: (1) The Cuban Boa is a generalist predator; (2) the diets of boas in natural and anthropogenic habitats differ; (3) an ontogenetic shift in diet occurs; and (4) foraging strategies used in natural and anthropogenic habitats differ. We identified 49 prey species from 351 prey items obtained from 218 snakes, including 71 items (31 snakes) from the literature. Mammals represented 55% of total prey items consumed, followed by birds (41%) and ectotherms (4%). Chilabothrus angulifer exhibited a narrow niche breadth. However, rather than a trophic specialist, we consider this boa an opportunistic generalist predator, capable of adjusting its diet and foraging behavior according to prey availability and abundance. The diet of Ch. angulifer changed dramatically from mostly native mammals and birds in natural habitats to mostly livestock, pets, and human com­mensals in human-altered habitats. Also, mammals were consumed more frequently in natural habitats, whereas birds dominated the diet of boas associated with anthropogenic habitats. Few ectotherms were consumed in either type of habitat. We observed an ontogenetic shift in diet, but this primarily reflected a trend of consuming larger prey rather than a shift from ectotherms to endotherms as reported for some other boids. In natural habitats, Ch. angulifer used both ambush and active-foraging modes by day and night, whereas in anthropogenic situations, most boas used an active-foraging strategy at night. The frequent consumption of domestic animals by Cuban Boas might be the principal reason for the historical human-wildlife conflict involving this species in rural areas of Cuba.

scholarly journals The Importance of Low-Intensive Agricultural Landscape for Birds of Prey

Land ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 252
Author(s):  
Emanuel Ștefan Baltag ◽  
Viorel Pocora ◽  
Lucian Eugen Bolboaca ◽  
Constantin Ion
Keyword(s):  
Agricultural Landscape ◽  
Diversity Index ◽  
Forest Edge ◽  
Natural Habitats ◽  
Common Buzzard ◽  
Trophic Networks ◽  
Heterogeneous Landscape ◽  
The Common ◽  
Breeding Seasons ◽  
Agricultural Areas

Low-intensive agricultural areas of Romania sustain high species diversity. Together with natural habitats, these areas are very important for European biodiversity. The ecosystem´s health is reflected in the predator status because of their position at the top of the trophic networks. The Common Buzzard (Buteo buteo) is the most common bird of prey species in Europe. During the first survey census conducted in Eastern Romania (2011–2012 breeding seasons), 8.55–10.35 breeding pairs/100 square km have been counted. The Common Buzzard density varies between breeding seasons and with differences in habitat structure. Their density is positively influenced by the density of forest edge and Simpson diversity index of habitats but is negatively influenced by the total habitat fragmentation and mean daily temperature. According to this analysis, the selection of breeding territories by common buzzards is positively influenced by a heterogeneous landscape in an area with low-intensive agriculture and with large areas of open habitats made up of natural or semi-natural vegetation.

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