DOI: 10.5061/dryad.vmcvdnd14
title: Public information use – are invasive demersal fish species more effective than natives?

description: Organisms determine environmental quality using their senses and personal
 experience (personal information), but can also use by-products of other
 individuals’ activities, i.e. public information. The ability to use
 public information originating from both con- and heterospecifics gives an
 advantage over individuals relying only on personal information or
 conspecific cues. The role of public information in invasion ecology is of
 high concern, as any differences in this aspect between alien and native
 species may determine the success of the former. Here we used two pairs of
 sympatric invasive and native demersal fish species (racer goby Babka
 gymnotrachelus / European bullhead Cottus gobio; monkey goby Neogobius
 fluviatilis / gudgeon Gobio gobio) facing two types of public cues
 (associated with frightened and foraging individuals) as a model to check
 if the invaders are more effective in public information use than the
 natives. Both invaders and the native gudgeon used danger cues from con-
 and heterospecifics, while the native bullhead failed to recognize
 heterospecific danger cues. The monkey goby and both native species appear
 to be attracted to foraging cues from donors less likely to exert
 competitive pressure on the observer (i.e. native species rather than
 potentially more aggressive invaders), while the racer goby appeared
 unable to correctly recognize heterospecific cues. Our results showed that
 public cues can enable invaders to read threats from a wide range of
 individuals and to find optimal food patches, which may contribute to
 their invasion success.
description: Uploaded data present the behavior of fish during the experiment
 assessing effectiveness in social information use. Test fish behavior was
 recorded, and, to minimize observer bias, we used the Ethovision XT® 10.1
 program to analyze it from the videos recorded.
 <strong>Experimental setup:</strong>
 We used LCD computer monitors to present the visual cues to the
 fish tested. The cues were prepared by recording particular behavior of
 demonstrators' individuals (antipredator behavior or foraging) and
 presenting them to the tested fish individual. The experimental setup
 consisted of a glass experimental tank (30 x 30 x 30 cm; length x width x
 height), with two computer monitors (BenQ GW2280-B, Taipei) placed on two
 opposite sides of the tank to display the stimulus videos (one monitor was
 to display visual cue, second one acted as a control). An IP camera
 (Samsung SNB-6004P, Changwon, South Korea) was placed 50 cm above the
 water surface to record the fish behavior.
 <strong>Behavior analysis:</strong>
 For Experiment 1 (antipredatory behavior), we set two zones on
 the experimental tank bottom, covering the whole tank width: (1) the
 “stimulus zone”, adjacent to the “stimulus” monitor (showing
 demonstrators), and (2) the “control zone”, adjacent to the monitor
 displaying the control sequence. We measured the time spent by the test
 fish in each zone (expressed as % of the total period time) and its
 general activity, expressed as the time spent on the move (% of the total
 period time). To analyze Experiment 2 (foraging), we
 set two zones on the experimental tank bottom: (1) the “foraging zone”,
 set up around the feeder on the monitor displaying foraging demonstrators,
 and (2) the “non-foraging zone” adjacent to the wall facing the monitor
 displaying the “control” sequence. We measured the time spent by the test
 fish in each zone (expressed as % of the total period time).
 For both experiments, we calculated zone preference indices using
 times spent by fish in particular zones in both experiments, according to
 the formula: ((time spent in the zone of interest) -
 (time spent in the other zone)) / ((time spent in the zone of interest) +
 (time spent in the other zone)) The value of “0” meant
 that the fish showed no preference for or avoidance of any zone. The
 positive and negative values meant that the fish showed a preference for
 or avoidance of the zone of interest, respectively.
 <strong>Statistics:</strong> To
 test the effects of observer species, demonstrator species, and period on
 zone preference index (Experiments 1 and 2) and general fish activity (in
 Experiment 1), we performed Linear Mixed Models (LMM), separate for each
 set of species and experiment. The observer species and demonstrator
 species were set as between-subject fixed effects, the period
 (pre-stimulus/flight response/inactive demonstrators in Experiment 1,
 pre-stimulus/stimulus in Experiment 2) as a within-subject fixed effect,
 and the test fish ID as a random effect. In both experiments, we
 interpreted the main effect of period and its interactions with other
 factors as indicators of fish reaction to different types of cues
 presented. The parametric test assumptions were not violated based on the
 visual inspection of residual plots.
description: # Public information use – are invasive demersal fish species more
 effective than natives?
 [https://doi.org/10.5061/dryad.vmcvdnd14](https://doi.org/10.5061/dryad.vmcvdnd14) ## Description of the data and file structure The main idea of the experiment: Our study aimed to investigate the ability of invasive fish to use public information. We tested fish arranged in two sets of species consisting of a co-existing invasive vs. native species: (1) racer goby *Babka gymnotrachelus* vs European bullhead *Cottus gobio*, (2) monkey goby *Neogobius fluviatilis* vs gudgeon *Gobio gobio.* We were interested in how the invaders integrate into freshwater communities in terms of exchanging (i.e., using and providing) information with native heterospecifics. In the first experiment, we checked if fish can recognize danger based on public information cues (antipredatory behavior) from con- and heterospecifics within each set of species. If so, we expected the test fish to avoid the area near the cue demonstrators and reduce their activity, as these are well-known antipredator behaviors. In the second experiment, we checked if fish can differentiate between foraging and non-foraging demonstrators of the public information cues. If so, we expected them to approach the foraging demonstrators. In both experiments, we confronted fish with conspecific and heterospecific cues within each set. Additionally, in the second experiment, we confronted the fish from the first set (racer goby and European bullhead) with heterospecific cues from the gudgeon. This native species is present in the Brda River, from which the racer goby and European bullhead were collected. This allowed us to check whether the native fish can recognize and discriminate between heterospecific cues released by two heterospecifics: one invasive and the other native. Also, we tested whether the invasive species reacted differently to the cues from different natives. The cue demonstrators were not used later in the experiment. ### Files and variables #### File: MA\_et\_al.*2023*-*Public\_cues\_about\_danger*.xlsx **Description:** The file contains data from the first experiment, where the fish were confronted with video material with other individuals exhibiting flight reactions. The file contains three sheets: "data bullhead racer" with the results for the European bullhead/racer goby set, "data gudgeon monkey" with the results for the gudgeon/monkey goby set, and "explanations" with details about abbreviations used (provided also below for clarity) and data collection. ##### Variables * SZ - time spent in the stimulus zone, expressed as the % of the total experiment time * CZ - time spent in the control zone, expressed as the % of the total experiment time * Mov - time spent on the move, expressed as the % of the total experiment time * Stim.pref - stimulus zone preference index, calculated using the formula provided in the "explanations" sheet #### File: MA\_et\_al.*2023*-\_Public\_cues\_from\_foraging.xlsx **Description:** The file contains data from the second experiment, where the fish were confronted with video material with other individuals exhibiting foraging behavior. The file contains three sheets: "data bullhead racer" with the results for the European bullhead/racer goby set, "data gudgeon monkey" with the results for the gudgeon/monkey goby set, and "explanations" with details about abbreviations used (provided also below for clarity) and data collection. ##### Variables * FZ - time spent in the stimulus zone, expressed as the % of the total experiment time * NZ - time spent in the control zone, expressed as the % of the total experiment time * For.pref - foraging zone preference index, calculated using the formula provided in the "explanations" sheet ## Code/software All analyses were performed using IBM SPSS Statistics 29.0 (IBM Corp.). ## Access information NA