Changes in trophic characteristics of common toad Bufo bufo, Mertens and Müller, 1928 (Bufonidae: Anura) during postmetamorphosis

Abstract

<p>Analiza ishrane je urađena na uzorcima 16 populacija vrste <em>Bufo bufo</em>, sa&nbsp;ukupno 356 adultnih jedinki. Od toga 8 uzoraka pripada podvrsti<em> B.b. bufo</em>-populacija sa 158, a 8 uzoraka <em>B.b spinosus</em> populacija sa 198 jedinki. Za analizu&nbsp;ishrane je kori&scaron;ćen i uzorak od 150 primjeraka, tek metamorfoziranih jedinki.&nbsp;Uzorci populacija su prikupljeni sa teritorije Srbije i Crne Gore. Ishranu ispitivanih&nbsp;podvrsta roda <em>Bufo</em>, na svim lokalitetima čine jedinke plijena isključivo predstavnici&nbsp;Invertebrata. Kod obje podvrste dominantan plijen su pripadnici reda Coleoptera i&nbsp;Hymenoptera kod <em>B.b. spinosus&nbsp;</em>(70,05%,16,92%), &nbsp;kod <em>B.b. bufo&nbsp;</em>(59,69%, 22,61%).&nbsp;Multivarijantna analiza urađena na ukupnom uzorku pokazujeda postoji statistički&nbsp;značajna zavisnost ispitivanih morfolo&scaron;kih karaktera žaba i promjenljive&nbsp;morfologije plijena. Korespodentna analiza je pokazala da jedinke obje &nbsp;podvrste&nbsp;preferiraju sličan plijen samo &scaron;to je učestalost tog plijena različita po podvrstama i&nbsp;polovima. Kod tek metamorfoziranih jedinki Anura na oba lokaliteta prisutan je isti&nbsp;plijen sa malim procentualnim razlikama. Prisustvo relativno visokog procenta&nbsp;Chironomidae ukazuje da ove jedinke nisu u potpunosti pre&scaron;le na terestrični način&nbsp;života. Dok prisustvo visokog procenta familija Formicidae i Byrrhidae ukazuje na&nbsp;<br />ishranu kojoj inače teže pripadnici vrste <em>B. bufo</em>, prelaskom na terestrični način&nbsp;života. Vrijednosti &scaron;irina trofičkih ni&scaron;a (B_A) po podvrstama pokazuju da je podvrsta <em>B.b. spinosus</em><i>&nbsp;</i>(B₁A=0,15) imala neznatno manju vrijednost u odnosu na podvrstu&nbsp;<em>B.b. bufo</em> (B₁A=0,16) , &scaron;to ukazuje na to da su pripadnici obje podvrste imale&nbsp;prilično ujednačenu ishranu. Na osnovu taksonomije plijena zabilježeno je veoma&nbsp;visoko preklapanje ni&scaron;a ishrane između podvrsta (95%). Veoma su oskudni&nbsp;literaturni podaci o ishrani ove dvije podvrste, &scaron;to podatke i rezultate ovog rada čini&nbsp;posebno vrijednim.</p>

<p>Diet analysis was conducted on the samples of 16 populations of species&nbsp;<em>Bufo bufo</em>, &nbsp;with total of 356 adult individuals. Among that, 8 samples belonged to&nbsp;sub-species <em>B.b. bufo</em> &ndash; population with 158 samples, and another 8 samples&nbsp;belonged to <em>B.b. spinosus</em>, with population of 198 individuals. For diet analysis we&nbsp;also used the sample of 150 individuals which have just finished metamorphosis.&nbsp;Population samples were collected from the territories of Serbia and Montenegro.&nbsp;The diet of investigated subspecies belonging to the genus <em>Bufo</em> from all localities,&nbsp;was composed of the Invertebrata exclusively. Coleoptera and Hymenoptera were dominant prey items in both groups <em>B.b. spinosus&nbsp;</em>(70.05%, 16.92%), and <em>B.b. bufo&nbsp;</em>(59.69%, 22.61%). Multivariate statistical analysis which was performed on the&nbsp;entire sample, showed existence of statistically significant dependence of&nbsp;morphological traits of common toadand variable morphology of prey. &nbsp;Correspondent analysis showed that individuals of both subspecies prefer similar&nbsp;prey, but the frequency of the prey occurance at different subspecies and sexes is&nbsp;different. Recently metamorphosed Anuran individuals from both localities, take&nbsp;the same prey with a small differences inpercentage. The presence of a relatively&nbsp;high percentage of Chironomidae indicates that these individuals are not completely&nbsp;moved on to terrestrial life. While the presence of a high percentage of the families&nbsp;Formicidae and Byrrhidae indicates a diet which usually species <em>B. bufo </em>aspire&nbsp;during the transition to terrestrial life. Values (B_A) of trophic niche width (B_A)&nbsp;indicate that the subspecies <em>B.b. spinosus&nbsp;</em>(B_A =15) had a slightly lower value&nbsp;compared to subspecies <em>B.b. bufo</em> (B_A =15) which indicates that both subspecies had&nbsp;a fairly uniform diet. Based on the taxonomy of prey, very high dietary &nbsp;niche&nbsp;overlap between subspecies was recorded (95%). Since there are very scarce&nbsp;<br />literature data about diet of the two subspecies, the data and results of this thesis are&nbsp;<br />particularly valuable.&nbsp;</p>