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1

Diet composition and prey selection of vendace Coregonus albula in the mesotrophic, temperate Lake Ostrowite (Northern Poland)

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Kakareko T. , Napiórkowski P. , Kozłowski J.

Oceanological and Hydrobiological Studies

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2008

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tom Vol. 37, No.1

57-68

EN

Lake Ostrowite is a mesotrophic lake in Northern Poland 280.7 ha in area and 43 m deep at its deepest point. To study vendace (Coregonus albula L.) diet in the lake, fish and zooplankton were sampled at two stations on 28-29 April, 15-16 May (fish only), 28-29 July and 15-16 August 2004. Fish were caught by gill netting, while zooplankton was collected from the whole water column by means of a Ruttner sampler (5 × 2 dm3). In total 91 vendace specimens were analysed, of which 64.8% had non-empty alimentary tracts. In the April and May samples Copepoda were the most numerous prey, while Daphnidae dominated the diet in the July- and September-caught fish. Planktonic Chironomidae pupae were also an important dietary item in the April-caught fish. Cladocerans, especially from Daphnidae family, were positively selected by vendace whilst copepods were not. Large predatory cladocerans, Leptodora kindtii, and the non-indigenous Bythotrephes longimanus were consumed in substantial quantities by the July- and Septembersampled fish, with the vendace feeding more intensively on the L. kindtii than on the B. longimanus.

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Diet and prey selection in Mehelyi's horseshoe bat Rhinolophus mehelyi (Chiroptera, Rhinolophidae) in the south-western Iberian Peninsula

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Salsamendi E. , Garin I. , Almenar D. , Goiti U. , Napal M. , Aihartza J.

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tom 10

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nr 2

EN

We studied diet and prey selection in Mehelyi's horseshoe bats Rhinolophus mehelyi in the south-western Iberian Peninsula, during the breeding seasons of 2003, 2006, and 2007. Faecal pellets were collected individually and arthropod fragments identified to family level, where possible. Arthropod availability was assessed using Malaise traps. Selection analyses were performed using Compositional Analysis and a Chi-square goodness-of-fit test. The bulk of the diet of R. mehelyi consisted of Lepidoptera, representing more than the 80% of the consumed volume on average (excluding juveniles), and more than 90% of the average percentage occurrence. This pattern was consistent across localities. Neuroptera and Tipulidae were locally abundant. Other important prey categories were Chrysomelidae, Brachycera, and Chironomidae. ANOVA tests showed that there were no significant differences between males and females in consumed prey categories, whereas juveniles consumed significantly less Lepidoptera than adults. Lepidoptera was the first prey category in the preference rank, followed by Myrmeleontidae, Chrysopidae and Tipulidae, and all of these were consumed more than expected by chance. This work shows that R. mehelyi is a moth specialist and suggests that juveniles may acquire this strategy while gaining hunting experience. Given the similarities in echolocation call characteristics and diet in the sibling R. mehelyi and R. euryale, they may compete for trophic resources in sympatry. Nevertheless, subtle differences in wing morphology between both species are probably large enough to permit spatial resource partitioning.

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Foods of the northern myotis, Myotis septentrionalis, from Missouri and Indiana, with notes on foraging

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Brack,Jr. V. , Whitaker,Jr. J. O.

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tom 03

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nr 2

EN

This paper presents information on foods eaten by the northern myotis, Myotis septentrionalis, from four different localities in the states of Missouri and Indiana, USA. Based on fecal and stomach content analyses, we found that M. septentrionalis feeds heavily on Lepidoptera (10.4-94.0% of the volume), and to a lesser extent on Coleoptera (0.4-64.0), Trichoptera (0.0-54.5), and Diptera (0.0-15.3). Non-flying prey items, such as spiders and lepidopterous larvae, made up 12.7% of food in 63 stomachs from Copperhead Cave, Indiana, which is a clear indication of the gleaning behavior of this species. Foraging was concentrated in the understory of non-riparian habitat, which may be a further reflection of a gleaning strategy. No significant differences were found in the overall diet of M. septentrionalis between evening and morning feeding periods, although there were some differences in consumption of particular orders.

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Evidence for prey selection by spotted hyaena in the Eastern Cape, South Africa

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Wentworth J. C. , Tambling C. J. , Kerley G. I. H.

Acta Theriologica

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2011

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tom 56

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nr 4

EN

We tested the widely accepted hypothesis that spotted hyaenas (Crocuta crocuta) are non-selective in their diet. The prey preference of spotted hyaena was studied in the Addo Elephant National Park (AENP), South Africa. Diet (frequency of occurrence of prey items in the diet) was quantified through the analysis of 55 scats, and compared with available prey. A combination of large- and medium-sized mammals (buffalo (Syncerus caffer), red hartebeest (Alcelaphus buselaphus) and common duiker (Sylvicapra grimmia) were the most preferred prey items. The most abundant species, warthog (Phacochoerus africanus) and kudu (Tragelaphus strepsiceros), were ignored and avoided, respectively. These results show that the assumption that hyaena prey on the most abundant available prey species may be overly simplistic. Predation patterns, such as the ones observed in AENP, may have important ramifications for less common species that are selected by hyaena in small enclosed reserves

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Diet and prey selection in Kuhl's pipistrelle Pipistrellus kuhlii [Chiroptera: Vespertilionidae] in South-Western Europe

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Goiti U. , Vecin P. , Garin I. , Salona M. , Aihartza J. R.

Acta Theriologica

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2003

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tom 48

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nr 4

EN

The trophic ecology of Kuhl's pipistrelle Pipistrellus kuhlii (Kuhl, 1817) was investigated monthly from May to October 1999. Nine insect and two arachnid orders were identified in faeces and classified in 24 different categories. The most frequently occurring prey categories were Culicidae, Lepidoptera, Chironomidae/Ceratopogonidae, Hymenoptera, unidentified Brachycera, Tipulidae and unidentified Coleoptera in decreasing order. Other categories exhibited seasonal importance, such as the coleopteran Rhizotrogus sp. Prey availability was evaluated monthly using Malaise traps in known feeding areas. Bats preyed selectively through a temporarily changing pattern. Some taxa constituted an important part of the diet and were positively selected either monthly or in most of the months. Many of them were the largest prey featuring in the diet and changes of their relative profitability across time would determine their selection index. The small size of some prey categories as well as P.kuhlii's morphofunctional constraints relative to flight and echolocation could explain their underexploitation or rejection. Our results suggest that P. kuhlii could be regarded as a 'selective opportunist' species.

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Breeding populations and diets of the Sparrowhawk Accipiter nisus and the Hobby Falco subbuteo in the Wigry National Park [NE Poland]

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Zawadzka D. , Zawadzki J.

Acta Ornithologica

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2001

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tom 36

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nr 1

EN

In 1990-1995,12-15 pairs of Sparrowhawks (9.1/100 km²) and 7-9 pairs of Hobbies (5.6 pairs/100 km²) inhabited the forest-lakeland area of the Wigry National Park (NE Poland). The diet composition of the two species was studied by the analysis of pellets and prey remains. Sparrowhawks fed on birds (97% of prey items, 99% of food biomass), especially Turdus spp., Parus spp. and Fringilla coelebs. Hobbies consumed birds (52% of prey, 94% of biomass) and insects (43% of prey, 1% of biomass). Sparrowhawks specialized in forest birds, positively selecting Parus spp., Turdus spp., Picidae and Ficedula spp. Hobbies hunted mainly birds of open habitats (Alauda arvensis) and woodland (Anthus trivialis).

PL

W latach 1990-1995 badano obszar 150 km². Zebrano wypluwki i szczątki zdobyczy w 6 rewirach lęgowych krogulca i 2 — kobuza. Ofiary identyfikowano na podstawie piór, kości, włosów oraz fragmentów pancerzyków i łusek okrywowych. Oszacowano biomasę pokarmu mnożąc liczbę ofiar przez średnią masę osobniczą danego gatunku. Szerokość nisz pokarmowych oceniono według Levinsa (1968), a wskaźnik nakładania się nisz według Pianki (1973). Preferencje obydwu gatunków drapieżników wobec ptaków porównano przy zastosowaniu wskaźnika selekcji Ivleva (Jacobs 1974). Danych o strukturze zgrupowań ptaków leśnych oraz ptaków terenów otwartych dostarczyły liczenia awifauny przeprowadzone w 1996 r. (4-7 razy na 13 powierzchniach próbnych). W poszczególnych latach stwierdzono 12-15 (średnio 13.7) rewirów lęgowych krogulca. Zagęszczenie tego gatunku wynosiło 9.1 par/100 km² powierzchni Parku, a szacunkowa wielkość rewiru lęgowego — 2.8 km². Krogulec gnieździł się w oddaleniu od brzegu lasu. Liczebność kobuza oceniono na 7-9 (średnio 8.3) par lęgowych, zagęszczenie — na 5.6 par/100 km², a rewir lęgowy obejmował ok. 12 km². Kobuz gniazdował blisko brzegu lasu, najczęściej zajmował puste gniazda kruka (89% przypadków). Głównym składnikiem pokarmu krogulca były ptaki leśne (Tab. 1), najczęściej drozdy, sikory, zięby i dzięcioły. Średnia masa ofiary wynosiła 34 g. W pokarmie kobuza dominowały ptaki środowisk otwartych (ponad 70% ofiar i 50% biomasy pokarmu), najczęściej drozdy, skowronek, świergotki (Tab. 2). Bardzo licznie chwytane owady miały znikomy udział w biomasie pożywienia. Średnia masa ofiary wynosiła 29 g. Szerokość niszy pokarmowej oceniana dla frekwencji ofiar była u kobuza dwukrotnie większa niż u krogulca, natomiast szerokości niszy oceniane dla biomasy pokarmu były u obydwu gatunków niemal równe (Tab. 1 i 2). Nisze pokarmowe kobuza i krogulca, oceniane na podstawie udziału biomasy 3 grup pokarmu (ssaków, ptaków i owadów), pokrywały się niemal całkowicie (α = 0.999). Do preferowanych ofiar krogulca w stosunku do ich ogólnego udziału w miejscowej awifaunie należały sikory, drozdy, dzięcioły, szpak, muchołówki i trznadel. Zięba była wyławiana proporcjonalnie do jej liczebności w środowisku. Kobuz preferował skowronka, świergotki i drozdy (Tab. 3). Rzadko chwytał ptaki typowo leśne. Zagęszczenia kobuza w Polsce wahają się w różnych lasach Polski od 1.2 do 7.4 par/100 km², z wyjątkiem Mazowsza, gdzie są niższe (0.5 par/100 km²). Zasiedlający przeważnie drągowiny świerkowe krogulec ma stosunkowo niskie zagęszczenia na południowym zachodzie Polski (gdzie przeważają lasy liściaste), a wyższe na północnym wschodzie, w lasach z dużym udziałem świerka (Tab. 4). Dane z piśmiennictwa europejskiego są zgodne z wynikami badań w WPN. W pokarmie krogulca dominują ptaki o masie od 7 g do 80 g (ponad 90% ofiar). Drapieżnik ten preferuje ptaki żyjące w lesie, unikając bardzo małych ofiar (np. mysikrólik, gatunki z rodzaju Phylloscopus). Źródła te podają też, że kobuzy licznie chwytają ptaki, najczęściej z terenów otwartych oraz latające owady.

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Diet composition and prey selection of vendace Coregonus albula in the mesotrophic, temperate Lake Ostrowite [Northern Poland]

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Kakareko T. , Napiorkowski P. , Kozlowski J.

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nr 1

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Patterns of wolf Canis lupus predation on wild and domestic ungulates in the Western Carpathian Mountains [S Poland]

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Nowak S. , Myslajek R. W. , Jedrzejewska B.

Acta Theriologica

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2005

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tom 50

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nr 2

EN

We studied the predator-prey relationships among wolvesCanis lupus Linnaeus, 1758, wild ungulates, and livestock in the managed mountain forests of the Western Carpathians (S Poland). Though roe deerCapreolus capreolus dominated in the community of wild ungulates and livestock was abundant within the study area, the three wolf packs preyed mainly on red deerCervus elaphus (42% of food biomass), and next on the roe deer (33%). In both species of deer, wolves preferred killing females and juveniles more frequently than expected from their respective shares in the populations. Wild boarSus scrofa made up 4% of the food biomass, in accordance with its low share in the ungulates community. Despite the easy access of wolves to numerous unprotected sheep flocks pastured on meadows among woods, livestock constituted only 3% of the wolf food biomass. Wolves preyed mostly on sheep (88%), killing on average 34 per year. Most cases of livestock depredation occurred in August –September, on pastures located most often >50 m apart from buildings. Usually, lack of proper guarding was conducive to wolf attacks.

9

Prey selection of the least weasel Mustela nivalis in the laboratory

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Pekkarinen P. , Heikkila J.

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1997

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tom 42

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nr 2

EN

Prey individuals representing the bank vole Clethrionomys glareolus and the field vole Microtus agrestis were presented in pairs to male and female least weasels Mustela nivalis Linnaeus, 1766 in the laboratory. The voles were placed in two randomly selected boxes out of 8 boxes, which were connected to an arena housing the weasel. For each trial we recorded the finding, killing and eating order of the two prey individuals. Mate weasels tended to kill bank voles before field voles, and female weasels preferred to eat the bank vole first. Both sexes selected juvenile bank voles as the first prey to eat.

10

Predation of Eurasian lynx on roe deer and red deer in Bialowieza Primeval Forest, Poland

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Okarma H. , Jedrzejewski W. , Schmidt K. , Kowalczyk R. , Jedrzejewska B.

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1997

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tom 42

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nr 2

EN

Patterns of lynx Lynx lynx {Linnaeus, 1758) predation on ungulates were studied in the Polish part of Białowieża Primeval Forest (580 km ) from scats and prey remains of iynx between 1985-1996, and radiotracking of IS lynx between 1991-1996, Cervids were the main prey and constituted 90% of food biomass consumed (analysis of faeces) and 84% of prey killed. Roe deer Capreotus capreolus was positively selected by all lynx (though stronger by females and subadults than by adult males). Fawns and adult roe deer of both sexes were preyed on in proportion to their abundance in the population. Red deer Ceruus elaphus was taken less often than would have been expected at random, and fawns were positively selected by lynx. On average, lynx spent 76 h (3.2 days) feeding on a killed deer (from 38 h in a female with 3 kittens to 105 h in single adult females). Mean searching time (ie time from leaving the remains of one deer to killing another one) was 52 h (2.2 days); from 10 h in a female with 3 young to 104 h in subadults. Thus, the average kill rate by lynx was one deer per 5.4 days. Predation impact of lynx population on roe and red deer was estimated in 1991-1996, when recorded numbers were 288-492 roe deer and 359-607 red deer per 100 km" in late winter (March), and 501-820 roe deer and 514-858 red deer per 100 km" in spring (May/June). During that period densities of deer declined markedly due to deliberately elevated hunting harvest by forestry personnel, aimed at reduction of game damage to silviculture. Densities of adult lynx were little variable (2.4-3.2 inds/100 km2), but reproduction rate strongly varied in response to deer decline, from 0.67 juv/adult lynx in 1991/92 to 0.25 juv/adult lynx in 1995/96. Annually, lynx population killed 110-169 roe deer/100 km2, which constituted 21-36% of spring (seasonally highest) numbers of roe deer. Lynx predation was the most important factor of roe deer mortality. Furthermore, lynx population took 42-70 red deer/100 km2 annually, which constituted 6-13% of spring number of red deer. In red deer mortality, lynx predation played an inferior role to hunting harvest and wolf predation.

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Does size matter? Relating consumed prey sizes and diet composition of otters in South Iberian coastal streams

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Clavero M. , Prenda J. , Delibes M.

Acta Theriologica

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2007

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tom 52

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nr 1

EN

We analysed seasonal changes in the sizes of prey [grey mullets (Mugilidae), flatfish (Soleidae), eelAnguilla anguilla and crayfishProcambarus clarkii] consumed by ottersLutra lutra Linnaeus, 1758 in a Mediterranean-climate coastal area and relate them to the frequencies of occurrence of each prey species in otter diet. The sizes of over 1500 otter prey were estimated from measurements of key pieces found in 814 otter spraints, which were collected in lower stream stretches in a sandy coastal area. Clear relationships between mean prey size and frequency of occurrence were observed for the four prey types. These relationships were positive for grey mullets, flatfish and crayfish (ie they occurred more in otter diet when more large individuals were predated), but was negative in the case of eels. Results suggest that these patterns could be related to seasonal changes in habitat use. Previous works in the study area showed that otter concentrate its predation efforts in freshwater stream stretches during spring and summer, when more and larger crayfish are available. Freshwater stretches have neither grey mullets nor flatfish, while eels are larger and scarcer there than near streams’ mouths, where crayfish is absent.

12

Predation by drilling gastropods and asteroids upon mussels in rocky shallow shores of southernmost South America: Paleontological implications

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nr 3

EN

To achieve a better understanding of predation pattern recorded in the fossil record it is essential to study predator−prey interactions in the modern seas. It includes the data collected from the field observations as well as from the experiments in captivity. Such an approach allows recognition of the bioeroders, its description and also provides quantification of these interactions. This work offers a case study of the traces of predation resulting from the predator−prey interactions between three mussels: Mytilus chilensis, Brachidontes purpuratus, and Aulacomya atra; and their five natural enemies: the gastropods Trophon geversianus, Xymenopsis muriciformis, and Acanthina monodon, and the asteroids Cosmasterias lurida and Anasterias antarctica living along the intertidal and/or subtidal rocky shores in Tierra del Fuego. The predatory damage to mussel shells varies according to the predator and prey species and techniques for attacking prey are highly specialized. A. monodon drills a hole in B. purpuratus but uses the outer lip of its shell as a wedge to open the valves of M. chilensis and A. atra. T. geversianus always makes holes, but while it drills the valve walls of M. chilensis, it prefers to drill the valve edges of A. atra and B. purpuratus, with different characteristic patterns. Usually the shells of mussels killed by C. lurida do not suffer from any mechanical damage, but some other shells were crushed or fractured along the margins. Comparatively, time required to successfully attack a prey was shorter in C. lurida (24 hours), followed by A. monodon (36 hours), and longer in T. geversianus (9 to 10 days). Traces of predation are not randomly distributed across size classes of mussel prey, reflecting selectivity for a particular size class. Also, drill holes are usually placed at specific sectors of the shell, indicating site selectivity. These observations offer some paleontological implications for investigating the pattern of predation in fossil record. They show that different patterns of shell damage can be due to different predator species (e.g., wall vs. edge drillings), although the same predator species can leave different marks when consuming different prey (e.g., T. geversianus). Most disconcerting for paleontologists are cases of predation which do not leave any marks on the prey shell detectable in the fossil record (e.g., predation by asteroids), or leave ambiguous marks (A. monodon when preying with the spine). In conclusion, besides the opportunity to identify some traces of predation by drilling gastropods in fossil mussels, this work gives criteria to address predation in some particular paleontological cases that would otherwise be dismissed by researchers.