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Mule deer spatial association patterns and potential implications for transmission of an epizootic disease

View Article: PubMed Central - PubMed

ABSTRACT

Animal social behaviour can have important effects on the long-term dynamics of diseases. In particular, preferential spatial relationships between individuals can lead to differences in the rates of disease spread within a population. We examined the concurrent influence of genetic relatedness, sex, age, home range overlap, time of year, and prion disease status on proximal associations of adult Rocky Mountain mule deer (Odocoileus hemionus hemionus) in a chronic wasting disease endemic area. We also quantified the temporal stability of these associations across different sex, age, and disease status classes. We used three years of high frequency telemetry data from 74 individuals to record encounters within 25 m of each other, and to calculate seasonal home range overlap measured by volume of intersection (VI). The strength of pairwise spatial association between adult mule deer was independent of genetic relatedness, age and disease status. Seasonal variation in association strength was not consistent across years, perhaps due to annual changes in weather conditions. The influence of home range overlap on association strength varied seasonally, whereby associations were stronger in pre-rut and fawning than in the rest of the seasons. The sexes of individuals also interacted with both VI and season. At increasing levels of VI, associations were stronger between females than between males and between females and males. The strongest associations in pre-rut were between males, while the strongest in rut were between females and males. The temporal stability of associations was markedly dependant on the sex and the diagnosis of the associating pair. Our findings highlight the importance of considering concurrent effects of biological and environmental factors when seeking to understand the role of social preference in behavioural ecology and disease spread. Applying this knowledge in epidemiological modelling will shed light on the dynamics of disease transmission among mule deer.

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Proportions of components in lagged association rate models among 44 adult mule deer in Saskatchewan, Canada.FF = female-female pairs, MM = male-male pairs, FM = female-male pairs; YY = young-young pairs, OO = old-old pairs, OY = old-young pairs; PP = positive-positive pairs, NN = negative-negative pairs, and PN = positive-negative pairs. Rapid disassociations were associations that lasted the sampling period (i.e. 1 day) at most. In constant companionships, the probability of re-association did not decay or increase over time within the context of the study period (i.e. 1 year). In casual acquaintances, the probability of re-association decayed over time, and their rate of decay was approximated from a1. In some cases, LARs of casual acquaintances decreased over 2 different time scales, one lasting longer (casual long) than the other (casual short). For formulae, and results on durations and SE, see S2 Appendix.
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pone.0175385.g006: Proportions of components in lagged association rate models among 44 adult mule deer in Saskatchewan, Canada.FF = female-female pairs, MM = male-male pairs, FM = female-male pairs; YY = young-young pairs, OO = old-old pairs, OY = old-young pairs; PP = positive-positive pairs, NN = negative-negative pairs, and PN = positive-negative pairs. Rapid disassociations were associations that lasted the sampling period (i.e. 1 day) at most. In constant companionships, the probability of re-association did not decay or increase over time within the context of the study period (i.e. 1 year). In casual acquaintances, the probability of re-association decayed over time, and their rate of decay was approximated from a1. In some cases, LARs of casual acquaintances decreased over 2 different time scales, one lasting longer (casual long) than the other (casual short). For formulae, and results on durations and SE, see S2 Appendix.

Mentions: The class LARs among 44 adult mule deer in 2011 were best described by either one of two models: (A) a model containing rapid disassociations, constant companionships and casual acquaintances, or (B) a model containing rapid disassociations and two levels of casual acquaintances, one lasting longer than the other (Fig 6; Table C in S2 Appendix). The LARs, which decreased over time, always remained above the association rate across all sex, age and CWD status classes (Figures A, B, C, D, E, F, G, H and I in S2 Appendix). Analyses between MM and YY associations produced cyclic-like patterns in the LARs (Figures G and H in S2 Appendix), and also values of SE and duration ranges that were implausible (e.g. 96 days on average ranging from 1 to 1) (Table G in S2 Appendix) despite several tests with different Jackknife levels.


Mule deer spatial association patterns and potential implications for transmission of an epizootic disease
Proportions of components in lagged association rate models among 44 adult mule deer in Saskatchewan, Canada.FF = female-female pairs, MM = male-male pairs, FM = female-male pairs; YY = young-young pairs, OO = old-old pairs, OY = old-young pairs; PP = positive-positive pairs, NN = negative-negative pairs, and PN = positive-negative pairs. Rapid disassociations were associations that lasted the sampling period (i.e. 1 day) at most. In constant companionships, the probability of re-association did not decay or increase over time within the context of the study period (i.e. 1 year). In casual acquaintances, the probability of re-association decayed over time, and their rate of decay was approximated from a1. In some cases, LARs of casual acquaintances decreased over 2 different time scales, one lasting longer (casual long) than the other (casual short). For formulae, and results on durations and SE, see S2 Appendix.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5384682&req=5

pone.0175385.g006: Proportions of components in lagged association rate models among 44 adult mule deer in Saskatchewan, Canada.FF = female-female pairs, MM = male-male pairs, FM = female-male pairs; YY = young-young pairs, OO = old-old pairs, OY = old-young pairs; PP = positive-positive pairs, NN = negative-negative pairs, and PN = positive-negative pairs. Rapid disassociations were associations that lasted the sampling period (i.e. 1 day) at most. In constant companionships, the probability of re-association did not decay or increase over time within the context of the study period (i.e. 1 year). In casual acquaintances, the probability of re-association decayed over time, and their rate of decay was approximated from a1. In some cases, LARs of casual acquaintances decreased over 2 different time scales, one lasting longer (casual long) than the other (casual short). For formulae, and results on durations and SE, see S2 Appendix.
Mentions: The class LARs among 44 adult mule deer in 2011 were best described by either one of two models: (A) a model containing rapid disassociations, constant companionships and casual acquaintances, or (B) a model containing rapid disassociations and two levels of casual acquaintances, one lasting longer than the other (Fig 6; Table C in S2 Appendix). The LARs, which decreased over time, always remained above the association rate across all sex, age and CWD status classes (Figures A, B, C, D, E, F, G, H and I in S2 Appendix). Analyses between MM and YY associations produced cyclic-like patterns in the LARs (Figures G and H in S2 Appendix), and also values of SE and duration ranges that were implausible (e.g. 96 days on average ranging from 1 to 1) (Table G in S2 Appendix) despite several tests with different Jackknife levels.

View Article: PubMed Central - PubMed

ABSTRACT

Animal social behaviour can have important effects on the long-term dynamics of diseases. In particular, preferential spatial relationships between individuals can lead to differences in the rates of disease spread within a population. We examined the concurrent influence of genetic relatedness, sex, age, home range overlap, time of year, and prion disease status on proximal associations of adult Rocky Mountain mule deer (Odocoileus hemionus hemionus) in a chronic wasting disease endemic area. We also quantified the temporal stability of these associations across different sex, age, and disease status classes. We used three years of high frequency telemetry data from 74 individuals to record encounters within 25 m of each other, and to calculate seasonal home range overlap measured by volume of intersection (VI). The strength of pairwise spatial association between adult mule deer was independent of genetic relatedness, age and disease status. Seasonal variation in association strength was not consistent across years, perhaps due to annual changes in weather conditions. The influence of home range overlap on association strength varied seasonally, whereby associations were stronger in pre-rut and fawning than in the rest of the seasons. The sexes of individuals also interacted with both VI and season. At increasing levels of VI, associations were stronger between females than between males and between females and males. The strongest associations in pre-rut were between males, while the strongest in rut were between females and males. The temporal stability of associations was markedly dependant on the sex and the diagnosis of the associating pair. Our findings highlight the importance of considering concurrent effects of biological and environmental factors when seeking to understand the role of social preference in behavioural ecology and disease spread. Applying this knowledge in epidemiological modelling will shed light on the dynamics of disease transmission among mule deer.

No MeSH data available.


Related in: MedlinePlus