Responses of mink to auditory stimuli: Prerequisites for applying the ‘cognitive bias’ approach

The aim of the study was to determine and validate prerequisites for applying a cognitive (judgement) bias approach to assessing welfare in farmed mink (Neovison vison). We investigated discrimination ability and associative learning ability using auditory cues. The mink (n = 15 females) were divided into two groups (High, n = 8; Low, n = 7, representing the frequency of the tone they were habituated to, 18 and 2 kHz respectively) and were tested using a habituation–dishabituation procedure in experiment 1. In experiment 2 one auditory stimulus was followed by an inter-trial-interval (safe/neutral situation), whereas another auditory stimulus was followed by an aversive stimulus (air blow) before the inter-trial-interval (danger situation). We observed behaviour including latencies to show a response during both experiments. The High mink showed significant habituation in experiment 1 but the Low mink only showed habituation in experiment 2. Regardless of the frequency used (2 and 18 kHz), cues predicting the danger situation initially elicited slower responses compared to those predicting the safe situation but quickly became faster. Using auditory cues as discrimination stimuli for female farmed mink in a judgement bias approach would thus appear to be feasible. However several specific issues are to be considered in order to successfully adapt a cognitive bias approach to mink, and these are discussed.     

Inter- and intraspecific variation in the genitalia of the ‘Melitaea phoebe group’ (Lepidoptera, Nymphalidae)

The ecology and phylogeny of the Melitaeini butterflies have received considerable attention in the last few years. Several publications have been based on research using molecular methods. Genital morphometry has already been published on two sibling species but without any accompanying taxonomic revision of related species or their intraspecific taxonomy. In this study the morphology of genitalia was analysed by landmark-based geometric morphometrics in males and by traditional morphometrics in females. Based on these morphological characters, the whole M. phoebe group (subg. Cinclidia) was revised. According to our results M. telona Fruhstorfer, 1908 is conspecific with M. ‘phoebe’ ornata Christoph, 1893. Thus, we consider M. telona a junior synonym of M. ornata, and we propose new combinations: M. ornata ornata Christoph, 1893, M. ornata telona Fruhstorfer, 1908, M. ornata amanica Rebel, 1917, M. ornata capreola Varga, 1967, M. ornata emipunica Verity, 1919, M. ornata enoch Higgins, 1941, M. ornata kovacsi Varga, 1967, M. ornata nigrogygia Verity, 1938, M. ornata ogygia Fruhstorfer, 1907 and M. ornata totila Stauder, 1914 based on the rule of priority. The validity of the species status of M. punica and M. scotosia was confirmed, whereas M. sibina and M. pseudosibina could not be separated from M. phoebe using morphometrics. A new species from Iran (Zagros Mts.) was described as M. zagrosi sp. n. In addition, the whole geographical range of M. ornata was reconsidered and some biogeographical connections were discussed. In M. ornata four morphotypes were found based on genitalia: 1. ‘Western type’: including the Italian, Hungarian and SW Ukrainian populations; 2. ‘Eastern type’: with a much extended distribution ranging from the Balkan Peninsula through Asia Minor to Kazakhstan; 3. ‘The Levant type’ (=M. ornata telona comb. nov.); 4. ‘Northern Iranian type’ (Kopeth Dagh and Elburz Mts.). The distribution of these morphotypes can be attributed to historic separation in distinct glacial refugia.     

Tryptophan-dependent indole-3-acetic acid biosynthesis by ‘IAA-synthase’ proceeds via indole-3-acetamide

Plants are suggested to produce their major growth promoting phytohormone, indole-3-acetic acid (IAA), via multiple redundantly operating pathways. Although great effort has been made and plenty of possible routes have been proposed based on experimental evidence, a complete pathway for IAA production has yet to be demonstrated. In this study, an in-vitro approach was taken to examine the conversion of l-tryptophan (l-trp) to IAA by gas chromatography-mass spectrometry (GC-MS). Especially the influence of putative reaction intermediates on the enzymatic conversion of l-trp to IAA was analyzed. Among the substances tested only indole-3-acetamide (IAM) showed a pronounced effect on the l-trp conversion. We additionally report that IAM is synthesized from l-trp and that it is further converted to IAA by the utilized cell free Arabidopsis extract. Together, our results underscore the functionality of an IAM-dependent auxin biosynthesis pathway in Arabidopsis thaliana.