scholarly journals Morphological correlates of prey consumed by Podarcis melisellensis (Braun, 1877) and P. siculus (Rafinesque, 1810) (Sauria, Lacertidae) from two mainland regions in the eastern Adriatic area

2013 ◽  
Vol 65 (3) ◽  
pp. 1015-1025
Author(s):  
S.Z. Stamenkovic ◽  
Rada Matic
Keyword(s):  
Resource Availability ◽  
Optimal Foraging ◽  
Morphological Traits ◽  
Prey Size ◽  
Morphological Characteristics ◽  
Optimal Foraging Theory ◽  
Variance Partitioning ◽  
Morphometric Data ◽  
Lizard Species ◽  
Trophic Resource

The correlation between trophic utilization and morphology was studied for two lizard species (Podarcis melisellensis and P. siculus) from two mainland localities in the eastern Adriatic area; this is the first report of trophic and morphometric data for P. melisellensis from mainland populations. Variance partitioning showed that most of the variation in morphological traits for the analyzed lizards was the result of differences between species, and to a lesser extent between sexes. Locality did not have a strong effect on the variation of morphological traits. Prey weight is the only characteristic of prey that generally exhibits correlations with morphological characteristics rather than prey size. The pattern of correlations is generally weaker for P. melisellensis than for P. siculus. Optimal foraging theory predictions were generally confirmed: P. siculus is more constrained by trophic resource availability, with a premium on larger and heavier prey consumed in the less productive locality (SM), which can be relaxed in more productive regions (KL). P. melisellensis shows such constraints only for males in the less productive region (SM). Females of both species consume heavier prey.

The First Record of Parthenitae and Cercariae of Plagiorchis Multiglandularis (Trematoda, Plagiorchiidae) in Lymnaea Stagnalis in Ukraine

2018 ◽  
Vol 52 (4) ◽  
pp. 289-294
Author(s):  
E. P. Zhytova
Keyword(s):  
Lymnaea Stagnalis ◽  
Morphological Characteristics ◽  
First Record ◽  
Morphometric Data ◽  
Diagnostic Characters ◽  
Plagiorchis Elegans

Abstract Parthenitae and cercariae of Plagiorchis. multiglandularis Semenov, 1927 are recorded in Lymnaea stagnalis (Linnaeus, 1758) for the fi rst time in Ukraine; their morphological characteristics are specifi ed. Diagnostic characters of P. multiglandularis parthenitae and cercariae found in Ukrainian Polissia are compared with those from other regions. To confi rm the validity of the species, a comparison of the morphometric data of this trematode larvae with the cercariae of Plagiorchis elegans (Rudolphi, 1802) Braun, 1902, found in molluscs L. stagnalis, L. ralustris and L. corvuses, was performed. It was determined that P. multiglandularis cercariae diff er from those of P. elegans in size and position of the penetration glands.

scholarly journals Be different to be better: the effect of personality on optimal foraging with incomplete knowledge

2021 ◽  
Author(s):  
Poppy M. Jeffries ◽  
Samantha C. Patrick ◽  
Jonathan R. Potts
Keyword(s):  
Optimal Foraging ◽  
Optimal Foraging Theory ◽  
Foraging Strategy ◽  
Foraging Strategies ◽  
Partial Knowledge ◽  
Marginal Value ◽  
Animal Populations ◽  
Plausible Mechanism ◽  
Insight Into ◽  
Modelling Approach

AbstractMany animal populations include a diversity of personalities, and these personalities are often linked to foraging strategy. However, it is not always clear why populations should evolve to have this diversity. Indeed, optimal foraging theory typically seeks out a single optimal strategy for individuals in a population. So why do we, in fact, see a variety of strategies existing in a single population? Here, we aim to provide insight into this conundrum by modelling the particular case of foraging seabirds, that forage on patchy prey. These seabirds have only partial knowledge of their environment: they do not know exactly where the next patch will emerge, but they may have some understanding of which locations are more likely to lead to patch emergence than others. Many existing optimal foraging studies assume either complete knowledge (e.g. Marginal Value Theorem) or no knowledge (e.g. Lévy Flight Hypothesis), but here we construct a new modelling approach which incorporates partial knowledge. In our model, different foraging strategies are favoured by different birds along the bold-shy personality continuum, so we can assess the optimality of a personality type. We show that it is optimal to be shy (resp. bold) when living in a population of bold (resp. shy) birds. This observation gives a plausible mechanism behind the emergence of diverse personalities. We also show that environmental degradation is likely to favour shyer birds and cause a decrease in diversity of personality over time.

Optimal foraging: theory and experiment

Nature ◽  
1977 ◽  
Vol 268 (5621) ◽  
pp. 583-584 ◽  
Author(s):  
John Krebs
Keyword(s):  
Optimal Foraging ◽  
Optimal Foraging Theory ◽  
Foraging Theory ◽  
Theory And Experiment
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