magistrsko delo
Barbara Jelen (Author), Dušan Devetak (Mentor)

Abstract

Larve volkcev (Neuroptera: Myrmeleontidae) so plenilske, a le nekatere gradijo posebne pasti - lijake za lov plena, medtem ko večina vrst na plen preži tik pod površino substrata in zgrabi plen s hitrimi gibi čeljusti in glave v smeri plena. Nekatere vrste lovijo plen na oba načina, z in brez lijaka. V okviru magistrskega dela smo v prvem sklopu raziskav ugotavljali učinkovitost v lovu plena pri štirih vrstah volkcev, dveh lijakarskih, Euroleon nostras in Myrmeleon formicarius in dveh nelijakarskih, Neuroleon microstenus in Distoleon tetragrammicus. Obe lijakarski vrsti smo opazovali tudi pri lovu brez lijaka. Volkci z lijaki so potrebovali bistveno manj časa za zgrabitev plena kot ostale larve brez lijakov. Prav tako so nelijakarske vrste plen zgrabile hitreje kot lijakarske brez lijakov. Pri vseh opazovanjih smo zabeležili še vzorce vedenja ob predstavitvi plena. Larve lijakarjev so se ob prisotnosti plena in brez lijakov vedle podobno kot larve v lijakih, je pa bila razlika v odzivnosti. Medtem ko se je večina larv v lijaku odzvala na plen, pa so se manj odzivale, ko so bile larve brez lijakov. Manj odzivne so bile larve E. nostras. Pri lijakarskih vrstah z lijakom in brez njih smo opazili pet različnih vzorcev vedenja, pri nelijakarskih vrstah pa dva. V drugem sklopu poskusov smo osebkom vrste E. nostras izmerili površine čeljusti s ščetinami in površine čeljusti brez ščetin. Površina, izmerjena s ščetinami, je bila bistveno večja od površine brez ščetin. Izmerili smo tudi razdalje med ščetinami in ugotavljali povezavo med temi razdaljami in velikostjo delcev substrata, ki ga larve najraje izberejo za gradnjo lijaka. V zadnjem sklopu poskusov smo opazovali prehranjevalno vedenje larv E. nostras v štirih različnih granulacijah substrata. Opazovali smo ulov plena in hranjenje. Iz posnetkov smo analizirali več faz hranjenja. Larve so najhitreje ulovile plen v za njih najustreznejši granulaciji. V grobih granulacijah so larve potrebovale več časa za ulov plena, zaradi večkratnega pobega plena iz lijaka, v finejši granulaciji pa so larve gradile manjše lijake in je prav tako plen lažje pobegnil. Na čas hranjenja (t.j. od zgrabitve plena do izmeta ostankov in od zgrabitve plena do razprtja čeljusti) granulacija nima vpliva. Med prehranjevanjem smo prepoznali 21 vedenjskih vzorcev v vseh granulacijah, od katerih je 10 značilnih za volkce v vseh granulacijah, posamezni pa se pojavijo le v določenih granulacijah. Larve so se bolj plastično vedle v za njih manj ustreznih granulacijah, kar sklepamo na osnovi frekvence in sekvence vedenjskih vzorcev.

Keywords

volkci;Myrmeleontidae;plenilsko vedenje;površina čeljusti;substrat;magistrska dela;Živalstvo;Magistrske naloge;Obnašanje živali;Plenilstvo;Ličinke volkcev;Euroleon sp.;Myrmeleon sp.;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UM FNM - Faculty of Natural Sciences and Mathematics
Publisher: [B. Jelen]
UDC: 595.74:591.131.2(043.2)
COBISS: 22390792 Link will open in a new window
Views: 991
Downloads: 86
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Other data

Secondary language: English
Secondary title: Predatory efficiency of the pit-building and non-pit-building antlions (Insecta: Neuroptera: Myrmeleontidae)
Secondary abstract: Antlion larvae (Neuroptera: Myrmeleontidae) are predatory insects. Few of the known species construct special pit-fall traps for prey capture, while most of the species waits for prey just beneath the substrate surface and capture prey with fast movement of the head and jaws towards the prey. Some species use both strategies for prey capture. In the first part of the master's thesis we investigate the effectiveness of prey capturing in four species of antlion larvae, two pit-building species, Euroleon nostras and Myrmeleon formicarius and two non-pit-building species, Neuroleon microstenus and Distoleon tetragrammicus. The effectiveness in prey capture in pit-building species was observed in larvae with pit-fall traps and without them. The pit-building species in pit-fall trap needed less time for prey capture in comparison to all other larvae. Non-pit-building species capture prey faster than pit-building larvae without pits. A large percent of pit-building larvae did not respond to the prey, when prey was presented to larvae without pits. E. nostras larvae without the pit were less responsive than larvae of M. formicarius. We noticed five different behavioural patterns in larvae of pit-building species when presented with prey, while in non-pit building species only two. In the second set of experiments we measured the surface area of the jaws and the jaws with bristles in E. nostras larvae. Surface of the jaws with bristles was substantially greater than the jaws without bristles, which was expected. We also measured the distance between the bristles and searched the relationship between the measured distance and particle size of the substrate that larvae prefer to live in. Further experiment regarding mentioned needs to be done to make conclusions. In the last part of the experiments we observed prey capture and feeding behaviour on E. nostras larvae in substrates with four different particle sizes. The feeding behaviour (form prey capture to jaw set) was divided into different phases and then compared. Larvae captured prey faster in the sand with the most suitable substrate granulation in comparison to other granulations. In coarser sand larvae required more time for capture especially due to multiple prey escape from the pit and in the finest sand probably due to the small size of the constructed pits. The granulations had no effect on the time of feeding. We have also observed behaviour. Most of behavioural patterns were similar in all granulations but only a few occurred in a certain granulation. Larvae showed more behavioural plasticity in unsuitable granulations, according to the frequencies and sequences of behavioural patterns.
Secondary keywords: antlions;Myrmeleontidae;predatory behaviour;prey capture;jaw surface;master theses;
URN: URN:SI:UM:
Type (COBISS): Master's thesis
Thesis comment: Univ. v Mariboru, Fak. za naravoslovje in matematiko, Oddelek za biologijo
Pages: VIII, 50 f.
ID: 9136518