Hybridization in bottlenose dolphins—A case study of Tursiops aduncus × T. truncatus hybrids and successful backcross hybridization events

Gridley, Tess; Elwen, Simon Harvey; Harris, Guillermo; Moore, Daniel M.; Hoelzel, A. Rus; Lampen, F.

doi:10.1371/journal.pone.0201722

Cited by 17 publications

(15 citation statements)

References 59 publications

(83 reference statements)

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“…This finding suggests that gene flow within Delphinidae may have continued for longer than shown by hPSMC, which may not be sensitive enough to detect the low rates of recent gene flow. Furthermore, persistent gene flow is supported by confirmed fertile contemporary hybrids between some of our study species; for example, bottlenose dolphins can produce fertile offspring with both Indo-Pacific bottlenose dolphins (Gridley et al, 2018) and Pacific white-sided dolphins (Crossman et al, 2016;Miyazaki et al, 1992). Either way, our hPSMC results within and between all three families show a consistent pattern of long periods of interspecific migration in Delphinoidea, some lasting up to more than ten million years post divergence.…”

Section: Cessation Of Gene Flowsupporting

confidence: 59%

A genomic assessment of the marine-speciation paradox within the toothed whale superfamily Delphinoidea

Westbury

Cabrera

Rey‐Iglesia

et al. 2020

Preprint

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Understanding speciation is a central aspect in Biology. The formation of new species was once thought to be a simple bifurcation process. However, recent advances in genomic resources now provide the opportunity to investigate the role of post-divergence gene flow in the speciation process. The diversification of lineages in the presence of gene flow appears almost paradoxical. However, with enough time and in the presence of incomplete physical and/or ecological barriers to gene flow, speciation can and does occur. Speciation without complete isolation seems especially likely to occur in highly mobile, wide ranging marine species, such as cetaceans, which face limited geographic barriers. The toothed whale superfamily Delphinoidea represents a good example to further explore speciation in the presence of interspecific gene flow. Delphinoidea consists of three families (Delphinidae, Phocoenidae, and Monodontidae) and within all three families, contemporary interspecific hybrids have been reported. Here, we utilise publicly available genomes from nine species, representing all three families, to investigate signs of post-divergence gene flow across their genomes, and to address the speciation processes that led to the diversity seen today within Delphinoidea. We use a multifaceted approach including: (i) phylogenetics, (ii) the distribution of shared derived alleles, and (iii) demography-based. We find that the divergence and evolution of lineages in Delphinoidea did not follow a simple bifurcating pattern, but were much more complex. Our results indicate multiple, long-lasting ancestral gene flow events both within and among families, which continued for millions of years after initial divergence.

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Section: Cessation Of Gene Flowsupporting

confidence: 59%

A genomic assessment of the marine-speciation paradox within the toothed whale superfamily Delphinoidea

Westbury

Cabrera

Rey‐Iglesia

et al. 2020

Preprint

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“…truncatus ), one female Indo-Pacific bottlenose dolphin ( T . aduncus ) and six hybrids (four female and two male) of the two species [ 50 ]. The individuals were held in three social groups (see Table 1 ) separated by gates which allowed partial visual and full acoustic contact, but not free movement between social groups.…”

Section: Methodsmentioning

confidence: 99%

Vocal correlates of arousal in bottlenose dolphins (Tursiops spp.) in human care

et al. 2021

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Human-controlled regimes can entrain behavioural responses and may impact animal welfare. Therefore, understanding the influence of schedules on animal behaviour can be a valuable tool to improve welfare, however information on behaviour overnight and in the absence of husbandry staff remains rare. Bottlenose dolphins (Tursiops spp.) are highly social marine mammals and the most common cetacean found in captivity. They communicate using frequency modulated signature whistles, a whistle type that is individually distinctive and used as a contact call. We investigated the vocalisations of ten dolphins housed in three social groups at uShaka Sea World dolphinarium to determine how patterns in acoustic behaviour link to dolphinarium routines. Investigation focused on overnight behaviour, housing decisions, weekly patterns, and transitional periods between the presence and absence of husbandry staff. Recordings were made from 17h00 – 07h00 over 24 nights, spanning May to August 2018. Whistle (including signature whistle) presence and production rate decreased soon after husbandry staff left the facility, was low over night, and increased upon staff arrival. Results indicated elevated arousal states particularly associated with the morning feeding regime. Housing in the pool configuration that allowed observation of staff activities from all social groups was characterised by an increase in whistle presence and rates. Heightened arousal associated with staff presence was reflected in the structural characteristics of signature whistles, particularly maximum frequency, frequency range and number of whistle loops. We identified individual differences in both production rate and the structural modification of signature whistles under different contexts. Overall, these results revealed a link between scheduled activity and associated behavioural responses, which can be used as a baseline for future welfare monitoring where changes from normal behaviour may reflect shifts in welfare state.

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“…Differences in behaviour between purebred and hybrid cetaceans has been reported [79]. Hybridisation of captive bottlenose dolphins and other dolphin species has been widely documented [58,[80][81][82], however hybridisation between bottlenose dolphin species in captivity has seldom been seen [see 49,83]. Although hybridisation is naturally occurring in 10% of animal species [84], in the wild there is little overlap of home ranges of Tusriops spp., limiting inter-species mating opportunities of bottlenose dolphins [49].…”

Section: Discussionmentioning

confidence: 99%

“…The dolphinarium consists of a covered and open-air pool network with seven interconnected pools of varying size with a combined volume of 11 000 m 3 . At the time of data collection in 2018, the dolphinarium housed ten bottlenose dolphins: three (two male and one female) common bottlenose dolphins (T. truncatus), one female Indo-Pacific bottlenose dolphin (T. aduncus) and six (four female and two male) hybrids of the two species [49]. The individuals were held in three social groups (see Table 1 for more information on the individuals and social groups) separated by gates which allowed partial visual and full acoustic contact, but not free movement between social groups.…”

Section: Methodsmentioning

confidence: 99%

Vocal correlates of arousal in bottlenose dolphins (Tursiopsspp.) in human care

Probert

Bastian

Elwen

et al. 2021

Preprint

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Human-controlled regimes can entrain behavioural responses and may impact animal welfare. Therefore, understanding the impact of schedules on animal behaviour can be a valuable tool to improve welfare, however information on overnight behaviour and behaviour in the absence of husbandry staff remains rare. Bottlenose dolphins ( Tursiops spp.) are highly social marine mammals and the most common cetacean found in captivity. They communicate using frequency modulated signature whistles which are individually distinctive and used as a contact call. We investigated the vocal behaviour of ten dolphins housed in three social groups at uShaka Sea World dolphinarium to determine how acoustic behavioural patterns link to dolphinarium routines. Investigation focused on overnight behaviour, housing decisions, weekly patterns, and transitional periods between presence and absence of husbandry staff. Recordings were made from 17h00 – 07h00 over 24 nights, spanning May to August 2018. Whistle production rate decreased soon after husbandry staff left the facility, was low over night, and increased upon arrival. Results indicated elevate arousal states associated with the morning arrival and presence of husbandry staff and heightened excitement associated with feeding. Housing in pool configurations which limited visual contact between certain groups were characterised by lower vocal production rates. Production of signature whistles was greater over the weekends compared to weekdays however total whistle production did not differ between weekends and weekdays. Heightened arousal associated with staff arrival was reflected in the structural characteristics of signature whistles, particularly maximum frequency, frequency range and number of whistle loops. Overall, these results revealed a link between scheduled activity and associated behavioural responses, which can be used as a baseline for future welfare monitoring where changes in normal behaviour may reflect shifts in welfare state.

show abstract

Hybridization in bottlenose dolphins—A case study of Tursiops aduncus × T. truncatus hybrids and successful backcross hybridization events

Cited by 17 publications

References 59 publications

A genomic assessment of the marine-speciation paradox within the toothed whale superfamily Delphinoidea

A genomic assessment of the marine-speciation paradox within the toothed whale superfamily Delphinoidea

Vocal correlates of arousal in bottlenose dolphins (Tursiops spp.) in human care

Vocal correlates of arousal in bottlenose dolphins (Tursiopsspp.) in human care

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