Wallace, R. B. | Search bioRxiv

bioRxiv2020

Mysterious disappearances of a large mammal in Neotropical forests

The drivers of periodic population cycling by some animal species in northern systems remain unresolved1. Mysterious disappearances of populations of the Neotropical, herdforming white-lipped peccary (Tayassu pecari, henceforth "WLP") have been anecdotally documented and explained as local events resulting from migratory movements or overhunting2,3,4, or as disease outbreaks5,6, and have not been considered in the context of large-scale species-specific population dynamics. Here we present evidence that WLP disappearances represent troughs in population cycles that occur with regular periodicity and are synchronized at regional and perhaps continent-wide spatial scales. Analysis of 43 disappearance events and 88 years of commercial and subsistence harvesting data reveals boom - bust population cycles lasting from 20 to 30 years, in which a rapid population crash occurring over 1 to 5 years is followed by a period of absence of 7 to12 years and then a slow growth phase. Overhunting alone cannot explain the crashes, but as in northern systems dispersal during the growth phase appears to play a key role. This is the first documentation of population cycling in a tropical vertebrate.

ecology↗

bioRxiv2019

Occupation and Parkinson disease in Women's Health Initiative Observational Study

IntroductionThere is a lack of consistency in associations between workplace factors and risk of Parkinson disease (PD), and paucity of such data on women. We took a classic occupational epidemiology approach that assesses associations with occupational groups in order to derive insights about potential occupation-specific exposures that may be causal. MethodsThe Womens Health Initiative (WHI-OS) is a prospective cohort that enrolled 91,627 postmenopausal women, 50 to 79 years of age from 10/01/93 to 12/31/98, at 40 clinical centers across the US with average follow-up of 11 years, who reported up to three paid jobs held the longest since age 18; these jobs were coded and duration of employment calculated. We defined the case by self-report of doctor-diagnosed PD (at baseline or follow-up), death attributed to PD, or medication consistent with PD. ResultsAmong 2,590 cases, we report evidence of excess risk among "counselors, social workers, and other community and social service specialists". There was a suggestion of increase in risk among post-secondary teachers, and "building and grounds cleaning and maintenance". There was also evidence of deficit in risk among women who worked in sales. Results with ever-employed and duration were similar, except for evidence of excess of risk among "health technologists and technicians" with more than 20 years of employment. Longer duration of life on a farm was associated with higher risk. ConclusionOur findings paint a largely reassuring picture of occupational risks for PD among US women, especially for trades largely unaffected by recent technological advances.

epidemiology↗