Dog-directed speech: why do we use it and do dogs pay attention to it?

Pet-directed speech is strikingly similar to infant-directed speech, a peculiar speaking pattern with higher pitch and slower tempo known to engage infants' attention and promote language learning. Here, we report the first investigation of potential factors modulating the use of dog-directed speech, as well as its immediate impact on dogs' behaviour. We recorded adult participants speaking in front of pictures of puppies, adult and old dogs, and analysed the quality of their speech. We then performed playback experiments to assess dogs' reaction to dog-directed speech compared with normal speech. We found that human speakers used dog-directed speech with dogs of all ages and that the acoustic structure of dog-directed speech was mostly independent of dog age, except for sound pitch which was relatively higher when communicating with puppies. Playback demonstrated that, in the absence of other non-auditory cues, puppies were highly reactive to dog-directed speech, and that the pitch was a key factor modulating their behaviour, suggesting that this specific speech register has a functional value in young dogs. Conversely, older dogs did not react differentially to dog-directed speech compared with normal speech. The fact that speakers continue to use dog-directed with older dogs therefore suggests that this speech pattern may mainly be a spontaneous attempt to facilitate interactions with non-verbal listeners

The Biology of Yellowtail (Seriola lalandi) in the Southern California Bight: Spatial Insights from Recreational Catch Records, Tagging and Life-History Characteristics.

Most organisms shift between different ecological niches or habitats throughout their lives. These shifts are prompted by growth and changing resource needs. In the marine realm, understanding why and when fish shift habitats is particularly important due to the increasing use of spatial management as a conservation strategy. Effective spatial management requires understanding how a species habitat usage changes throughout its’ lifespan.Within the Southern California Bight (SCB)Yellowtail (Seriola lalandi) are iconic gamefish and widely targeted throughout the region, both in U.S. and Mexican territorial waters. Their cross-border movements mean these fish encounter a diverse array of anthropogenic pressures, ranging from ocean-warming to agricultural and urban run-off to significant recreational, artisanal, and commercial fishing.This work attempts to understand and quantify how yellowtail use the Southern California Bight and how that usage affects their biology. This was carried out in 3 separate chapters dealing with analysis of long-term recreational catch records, conventional tagging, passive acoustic telemetry as well as spatially-explicit analysis of age, growth, diet and trophic position.The primary differences detected across all investigated parameters were size-mediated. Thus, one contiguous population with distinct ontogenetic shifts in habitat and diet is the most parsimonious explanation for the results from each chapter presented in this thesis. Recreational catch data showed inshore and offshore catch sizes were different between years and across seasons and fish size, rather than tagging season best explained detection rates of acoustically tagged fish. These findings supported claims by recreational anglers that large fish caught inshore are potentially year-round SCB residents. The conclusion of one, panmictic, SCB yellowtail population is further supported by results from life-history analysis as fish size again was the only source of significant differences in age/growth, diet, or trophic position regardless of sampling location or region.Results from tag returns, acoustic telemetry and life-history analysis indicate that there is likely one contiguous population of yellowtail in the SCB and that due to highlevels of fishing pressure, this population may be reliant on seasonal influxes of fish from the south to sustain current fishing levels

Keren, a new ligand of the Drosophila epidermal growth factor receptor, undergoes two modes of cleavage

Spitz (Spi) is the most prominent ligand of the Drosophila EGF receptor (DER). It is produced as an inactive membrane precursor which is retained in the endoplasmic reticulum (ER). To allow cleavage, Star transports Spi to the Golgi, where it undergoes cleavage by Rhomboid (Rho). Since some DER phenotypes are not mimicked by any of its known activating ligands, we identified an additional ligand by database searches, and termed it Keren (Krn). Krn is a functional homolog of Spi since it can rescue the spi mutant phenotype in a Rho- and Star-dependent manner. In contrast to Spi, however, Krn also possesses a Rho/Star-independent ability to undergo low-level cleavage and activate DER, as evident both in cell culture and in flies. The difference in basal activity correlates with the cellular localization of the two ligands. While Spi is retained in the ER, the retention of Krn is only partial. Examining Spi/Krn chimeric and deletion constructs implicates the Spi cytoplasmic domain in inhibiting its basal activity. Low-level activity of Krn calls for tightly regulated expression of the Krn precursor

Intracellular trafficking by Star regulates cleavage of the Drosophila EGF receptor ligand Spitz

Spitz (Spi) is a TGFα homolog that is a cardinal ligand for the Drosophila EGF receptor throughout development. Cleavage of the ubiquitously expressed transmembrane form of Spi (mSpi) precedes EGF receptor activation. We show that the Star and Rhomboid (Rho) proteins are necessary for Spi cleavage in Drosophila cells. Complexes between the Spi and Star proteins, as well as between the Star and Rho proteins were identified, but no Spi–Star–Rho triple complex was detected. This observation suggests a sequential activity of Star and Rho in mSpi processing. The interactions between Spi and Star regulate the intracellular trafficking of Spi. The Spi precursor is retained in the periphery of the nucleus. Coexpression of Star promotes translocation of Spi to a compartment where Rho is present both in cells and in embryos. A Star deletion construct that maintains binding to Spi and Rho, but is unable to facilitate Spi translocation, lost biological activity. These results underscore the importance of regulated intracellular trafficking in processing of a TGFα family ligand

Spatial ecology of the Giant Sea Bass, Stereolepis gigas, in a southern California kelp forest as determined by acoustic telemetry.

The fisheries history of the Giant Sea Bass, Stereolepis gigas (Telostei: Polyprionidae), is closely linked to its spatial ecology. Its overharvest is directly associated with formation of spatially distinct spawning aggregations during summer, while its subsequent recovery is hypothesized to be the result of spatially explicit gear restrictions. Understanding the spatial ecology of Giant Sea Bass is a key part of efforts to assess contemporary threats such as commercial harvest and incidental catch by recreational fisheries. In this study, we used acoustic telemetry to characterize Giant Sea Bass space use in the La Jolla kelp forest using an acoustic array that encompasses two marine protected areas (MPAs) and heavily trafficked recreational fishing grounds. Five of the seven fish we tagged remained in the La Jolla array for at least 6 months. Two fish were resident across multiple years, with one fish consistently detected for 4 years. Only one fish was detected in the broader network of regional acoustic receivers, moving north approximately 8 km to Del Mar. Most tagged fish had home ranges and core use areas indicating they spend considerable time outside MPAs, particularly in areas with high recreational fishing activity. During spawning season we detected fish less frequently in the La Jolla array and recorded higher movement rates. While the current MPA network in La Jolla by no means offers complete protection to this fish, it does appear to support long-term persistence of some individuals in a region of exceptionally high recreational fishing pressure