Goldfish and oscars have comparable responsiveness to dipole stimuli

The relative roles of the fish lateral line and inner ear for the perception of hydrodynamic stimuli are poorly investigated. Here, we studied responsiveness to a 100 Hz vibrating sphere (dipole stimulus) of goldfish and oscars, two species that differ in peripheral lateral line morphology, inner ear morphology, mechanical linkage between inner ear and swim bladder, and inner ear sensitivity. We measured unconditioned dipole-evoked changes in breathing activity in still water and in the presence of a 5-cm s⁻¹ background flow. In still water, individuals from both species responded to sound pressure levels (SPLs) between 92 and 109 dB SPL re 1 μPa_RMS. Responsiveness was not affected by background flow or by temporary inactivation of the lateral line. The data suggest that fish with different lateral line and inner ear morphologies have similar sensitivities to vibrating sphere stimuli and can detect and respond to dipole sources equally well in still water and in moderate background flows. Moreover, behavioral responses were not dependent on a functional lateral line, suggesting that in this type of experiment, the inner ear is the dominant sense organ for the perception of hydrodynamic stimuli.     

Mirror,mirror on the wall: the predictive value of mirror tests for measuring aggression in fish

The behaviour of animals towards their mirror image (“mirror test”) is routinely used as a proxy to measure aggression levels, especially in fish. The lack of evidence for visual self-recognition in fish supports this method. However, recent work points towards different hormonal and gene expression responses when fish are exposed either to conspecific opponents or to their mirror image, urging for validation of this widespread method. Here, we test the predictive value of mirror tests in three sympatric cichlid species from Lake Tanganyika: the cooperative breeder Neolamprologus pulcher, the polygamous shell brooder Telmatochromis vittatus and the monogamous, biparental piscivore Lepidiolamprologus elongatus. In particular, we compare differences in restrained and overt aggression levels for individuals of each species when confronted with a mirror or a live conspecific. The three species differed in response to the two contest situations. While in N. pulcher both aggressive responses were correlated between the mirror test and the live opponent fight, there was no such relationship in T. vittatus and L. elongatus. Thus, the mirror test appears to be a suitable surrogate for intraspecific aggression in N. pulcher, while aggression against a mirror image has limited predictive value for intraspecific aggression in the other two species. These results underline the importance of validating the mirror test’s predictive value in a study species before drawing conclusions from mirror tests about aggressiveness under natural, social conditions.     

Determination of carbamazepine and 12 degradation products in various compartments of an outdoor aquatic mesocosm by reliable analytical methods based on liquid chromatography-tandem mass spectrometry

Environmental Science and Pollution Research - The aims of this work are to develop suitable analytical methods to determine the widely used anticonvulsant carbamazepine and 12 of its...     

Response to Kruse-Plass et al. (2017) regarding the risk to non-target lepidopteran larvae exposed to pollen from one or more of three Bt maize events (MON810, Bt11 and 1507)

We respond to the paper of Kruse-Plass et al. (Environ Sci Eur 29:12, 2017), published in this journal, regarding the risk to non-target lepidopteran larvae exposed to pollen from one or more of three Bt maize events (MON810, Bt11 and 1507). We emphasise that what is important for environmental risk assessment is not the number of pollen grains per se, but the degree of exposure of a NT lepidopteran larva to Bt protein contained in maize pollen. The main text of this response deals with general issues which Kruse-Plass et al. have failed to understand; more detailed refutations of each of their claims are given in Additional file 1. Valid environmental risk assessment requires direct measurement of pollen on leaves at varying distances outside a source field(s); such measurements reflect the potential exposure experienced by an individual larva on a host plant. There are no new data in the Kruse-Plass et al. paper, or indeed any data directly quantifying pollen on actual host-plant leaves outside a maize field; only data gathered within or at the edge of maize crops were reported. Values quoted by Kruse-Plass et al. for deposition on host plants outside the field were estimates only. We reiterate the severe methodological criticisms made by EFSA [Relevance of a new scientific publication (Hofmann et al. 2016) for previous environmental risk assessment conclusions and risk management recommendations on the cultivation of Bt-maize events MON810, Bt11 and 1507. EFSA Supp Publ; EN-1070, 2016], which render this estimation procedure unreliable. Furthermore, criticisms of EFSA (EFSA J 2015(13):4127, 2015) and of EFSA [Relevance of a new scientific publication (Hofmann et al. 2016) for previous environmental risk assessment conclusions and risk management recommendations on the cultivation of Bt-maize events MON810, Bt11 and 1507. EFSA Supp Publ; EN-1070, 2016] made by Kruse-Plass et al. are shown in Additional file 1 to be without foundation. We therefore consider that there is no valid evidence presented by Kruse-Plass et al. to justify their conclusions.