Predator foraging behavior: effect of a novel prey species on prey selection by a marine intertidal gastropod

1990 ◽  
Vol 139 (1-2) ◽  
pp. 101-117 ◽  
Author(s):  
Michael L. Carroll ◽  
David S. Wethey
2018 ◽  
Vol 70 (1) ◽  
Author(s):  
Serena J. Randolph ◽  
Alan D. Maccarone

Abstract Predation on bivalve mollusks by gastropod mollusks is common in coastal regions of the United States; however, few previous studies have examined whether drilling gastropods exhibit prey selection. In 2016, shells with small holes drilled by as many as two gastropod predators were collected at three sites separated by 30 km along the Texas Upper Gulf Coast on the Bolivar Peninsula (29° 40′N, 94° 90′W). The likeliest predators in these waters are the southern oyster drill (Stramonita haemastoma Linnaeus 1767) and the moon snail (Neverita duplicate Say 1822). Collected shells were identified to species and measurements were taken to examine statistical relationships between predators and prey species. These measurements included drill-hole diameter, shell thickness, drill-hole completeness, number of drill attempts, and collection site. Across the three locations, 17 different species of shells with drill holes were collected; of these, we focused on the ten most abundant species (n = 277 shells). The sample showed high variation in drill-hole diameter, shell thickness, and drill-hole completeness. Both the total number of holes and mean drill-hole diameter differed significantly among prey species (ANOVA, both P < 0.0001). In addition, drill-hole diameter correlated directly with prey shell thickness (P < 0.0001). Shells whose drill holes were complete were significantly thinner than shells with incomplete holes (P < 0.0001). Mean prey shell thickness, mean drill-hole diameter, and mean number of drill holes all differed significantly by collection site (all P < 0.0001). Ecological and morphological implications related to gastropod predation on mollusks are discussed.


2020 ◽  
Vol 21 (11) ◽  
Author(s):  
KHWANRUTAI CHARASPET ◽  
Ronglarp - Sukmasuang ◽  
NORASET KHOEWSREE ◽  
MANANYA PLA-ARD ◽  
YUWALUK CHANACHAI

Abstract. Charaspet K, Sukmasuang R, Khoewsree N, Pla-ard M, Chanachai Y. 2020. Prey species and prey selection of dholes at three different sites in Thailand. Biodiversitas 21: 5248-5262. The study of prey species and prey selection of Dholes at 3 different sites was conducted at Khao Yai National Park, Salak Pra, and Huai Kha Khaeng Wildlife Sanctuaries from 2013 to 2020. Information on Dhole prey at the sites was collected from the residues of dhole scats, from which the selection index, the relative biomass of the prey, and the relative amounts of the consumed prey were calculated. The data were collected simultaneously with the use of camera traps at each site. The study revealed that there were 13 species of Dhole prey with body weight over 5 kg. The result indicated that there were 7 species of even-toed ungulates. The relative biomass of even-toed ungulates ranged between 76.78 - 90.50% of the total biomass of all the Dholes’ consumed prey for all study sites. The dietary diversity index unveiled a similar index in all areas, which proved the adequacy of the analyzed scats. However, the Niche breadth index, which indicates the relevance of prey selection and prey species to the appearances of the prey at each site, was found to be high at Huai Kha Khaeng Wildlife Sanctuary, Khao Yai National Park, while the index was found to be low at Salak Pra Wildlife Sanctuary. The results revealed that Dholes consumed viverrid species and Malayan porcupine more often at the site where there were large carnivores. The recommendation from this study was the conservation and restoration of the ungulate populations, the main prey, as it greatly affects the conservation of the Dhole populations in Thailand.  Grassland and salt lick sites, water sources improvements are also important to promote prey population. The conservation of wildlife prey by releasing them to nature, as currently conducted, has an effect on the increase of Dholes’ prey species.


2020 ◽  
Vol 28 (2) ◽  
pp. 155-179
Author(s):  
Nuno Onofre ◽  
Luís Sampaio

The diet of Short-toed Snake-eagle (Circaetus gallicus) during the breeding season in an area dominated by cork and holm oak parkland forests (Montados) was analyzed in this study. As expected, results showed that snakes are the dominant prey in the diet of this eagle, comprising up to 92.5% of the identified items, if potential secondary prey species were excluded. The Montpellier Snake (Malpolon monspessulanus) was the most consumed one (42.2%), followed by the Ladder Snake (Zamenis scalaris) (28.0%), and the water snakes (Natrix spp.) (14.2%). According to the same criteria, lizards (mainly Psammodromus algirus) and mammals represent between 4.8 and 2.2%, respectively. Other animals such as pond turtle and amphibians are irregular prey (<1%), and no bird remains were found at all. Short-toed Snake-eagle is usually referred as a stenophagic predator where snakes are by far its most important prey type, and where within this taxonomic group it behaves as a generalist predator. In this study this premise was then tested comparing the relative abundance of the snake species with their proportion in the diet composition of the eagle in order to know whether or not prey selection exists with regard to the species of snakes in this region. Results point to a quite plausible "preference" for the Ladder Snake and an "avoidance" for the smooth snakes group (Macroprotodon brevis/Coronella girondica), and possibly for the Horseshoe Whip (Hemorrhois hippocrepis). The avoidance to the Horseshoe Whip must be indirect and habitat related, while in relation to the two smooth snakes it may be due in large extend to its small size, in particular.


Author(s):  
Manuela Bassoi ◽  
Eduardo R. Secchi ◽  
Daniel Danilewicz ◽  
Ignacio B. Moreno ◽  
Roberta A. Santos ◽  
...  

Abstract The franciscana dolphin (Pontoporia blainvillei) is a coastal dolphin endemic to the western South Atlantic Ocean. The dolphin is listed as vulnerable in the IUCN Red List, with incidental catches in gillnet fisheries the greatest conservation concern for this species. Insights into the feeding habits of this dolphin are essential to understand its distribution, movements and use of habitat, which are fundamental for effective management of the species. The feeding habits of franciscana dolphins were investigated from analyses of stomach contents of animals incidentally caught by two fishing operations from southern and northern regions of the southern Brazilian coast. In this study we investigate the existence of intrapopulation (sexual maturity and sex-related) variation in the diet of the franciscana dolphin, evaluating the spatial (northern and southern geographic areas) and seasonal influences. The analyses were based on Linear and Generalized Linear Models (LM and GLM). The majority of identified prey species were bottom-dwelling teleosts and the squid Doryteuthis sanpaulensis. The most important prey differed spatially and seasonally between northern and southern regions of the study area, and our results revealed significant differences between sexes and sexual maturity stages, mainly related to prey species sizes. This variation might indicate differences in prey selection, availability or habitat use patterns among these groups. In any case, these dietary differences are likely to minimize intraspecific competition for food resources, and/or indicate spatio-temporal variation in prey availability.


2004 ◽  
Vol 133 (3) ◽  
pp. 504-514 ◽  
Author(s):  
Brian D. S. Graeb ◽  
John M. Dettmers ◽  
David H. Wahl ◽  
Carla E. Cáceres

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