Environment and Local Substrate Availability Effects on Harem Formation in a Polygynous Bark Beetle.

Many forms of polygyny are observed across different animal groups. In some species, groups of females may remain with a single male for breeding, often referred to as "harem polygyny". The environment and the amount of habitat available for feeding, mating and oviposition may have an effect on the formation of harems. We aimed to determine how the surrounding environment (a harvested or unharvested pine plantation) and availability of local substrate affect the harems of the bark beetle, Ips grandicollis (Coleoptera: Curculionidae: Scolytinae). In a harvested pine plantation with large amounts of available habitat, the population density of these beetles is much higher than in unharvested plantations. We found the number of females per male to be significantly greater in the harvested plantation than the unharvested one. Additionally, the amount of substrate available in the immediate local vicinity (the number of logs in replicate piles) also influences the number of beetles attracted to a log and size of individual harems. We also examined how females were distributing themselves in their galleries around the males' nuptial chamber, as previous work has demonstrated the potential for competition between neighbouring females and their offspring. Females do not perform clumping, suggesting some avoidance when females make their galleries, but they also do not distribute themselves evenly. Female distribution around the male's nuptial chamber appears to be random, and not influenced by other females or external conditions.

Coping, PTSD symptoms, and alcohol involvement in trauma-exposed college students in the first three years of college.

The objective of the present study was to examine prospective, bidirectional associations among posttraumatic stress disorder (PTSD) symptoms, coping style, and alcohol involvement (use, consequences) in a sample of trauma-exposed students just entering college. We also sought to test the mechanistic role that coping may play in associations between PTSD symptoms and problem alcohol involvement over time. Participants (N = 734) completed measures of trauma exposure, PTSD symptoms, coping, and alcohol use and consequences in September of their first college year and again each September for the next 2 years. We observed reciprocal associations between PTSD and negative coping strategies. In our examination of a mediated pathway through coping, we found an indirect association from alcohol consequences and PTSD symptoms via negative coping, suggesting that alcohol consequences may exacerbate posttraumatic stress over time by promoting negative coping strategies. Trauma characteristics such as type (interpersonal vs. noninterpersonal) and trauma reexposure did not moderate these pathways. Models were also invariant across gender. Findings from the present study point to risk that is conferred by both PTSD and alcohol consequences for using negative coping approaches, and through this, for posttraumatic stress. Interventions designed to decrease negative coping may help to offset this risk, leading to more positive outcomes for those students who enter college with trauma exposure.

Posttraumatic stress symptoms and alcohol problems: self-medication or trait vulnerability?

BACKGROUND AND OBJECTIVES: Posttraumatic stress symptoms (PTSD) and problem alcohol use (ALC) commonly co-occur, but the nature of this co-occurrence is unclear. Self-medication explanations have been forwarded, yet traits such as tendency toward negative emotionality and behavioral disconstraint also have been implicated. In this study we test three competing models (Self-Medication, Trait Vulnerability, Combined Dual Pathway) of PTSD-ALC prospectively in a college sample. METHOD: Participants (N=659; 73% female, M age=18) provided data at college matriculation (Time 1) and 1 year later (Time 2). RESULTS: Structural equation models showed disconstraint to meditate the path from PTSD symptoms to alcohol problems, supporting a trait vulnerability conceptualization. Findings regarding negative emotionality and self-medication were more mixed. Negative emotionality played a stronger role in cross-sectional than in prospective analyses, suggesting the importance of temporal proximity. CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE: Self-regulation skills may be an important focus for clinicians treating PTSD symptoms and alcohol misuse disorders concurrently.

Recent sexual victimization and drinking behavior in newly matriculated college students: a latent growth analysis.

College matriculation is a time of developmental and social change and is often a time of heavy drinking. Sexual victimization (SV) is prevalent in late adolescence and poses additional risk for problem drinking behavior. Thus, matriculating students with a SV history may be at heightened risk for maladaptive alcohol use while transitioning through the first year of college. Furthermore, victimization that has occurred close to college matriculation may confer particular risk for problem alcohol use, because the added stressor of coping with a SV while negotiating the transition into college may lead to risky drinking behavior. Therefore, examining the influence of SV timing (i.e., recency) on drinking patterns in freshman year was the aim of the present study. Matriculating undergraduates with a history of SV were assessed at six points during freshman year. Using latent growth curve modeling, we tested differences in trajectories of drinking behavior (i.e., alcohol use, binge drinking) between students who reported a recent SV and those who reported a more distal SV. Students endorsing a recent SV evidenced greater overall levels of alcohol use and higher levels of binge drinking than individuals with SV that was less recent. Moreover, the recent SV group showed significantly more variability in drinking outcomes over freshman year, with escalations mapping onto more salient periods of transition over the first college year. SV that occurs close to college entry is associated with specific and persistent risk for maladaptive drinking behavior in newly matriculated college students.

Prospective effects of method of coercion in sexual victimization across the first college year.

Women who enter college with a sexual victimization (SV) history may be at particular risk for deleterious outcomes including maladaptive alcohol involve posttraumatic stress, and re-victimization. Further, pre-college SV may be an impediment for the achievement of academic mile and may negatively impact the transition into college. Recent work shows that the method of coercion used in SV may be an important predictor of post-victimization outcomes. As such, the identification of pathways between type of SV and outcomes can aid in early identification and intervention for those at highest risk. In a sample of newly-matriculated female college students, this study examined unique outcomes associated with two specific types of SV, (1) threats/use of physical force (Force SV) or (2) incapacitation (Incap SV). Participants completed assessments of SV, alcohol involvement, posttraumatic stress, and academic outcomes at 6 time-points over their first year of college. Results showed differential outcomes based on pre-matriculation exposure to Force SV or Incap SV. Women with Incap SV were higher on problem drinking indices whereas women with Force SV were at greater risk for re-victimization and marginally more PTSD symptoms. Having a history of either type of SV predicted attrition, but there were no differences when comparing Force SV to Incap SV. Overall, results from this study support the utility of delineating SV experiences by method of coercion, and point to the potential of highlighting different outcomes in tailored intervention programs.

Socioeconomic status and inflammatory processes in childhood asthma: the role of psychological stress.

BACKGROUND: Although social environment variables such as socioeconomic status (SES) have been linked to childhood asthma, little is known about the psychobiological mechanisms underlying this relationship. OBJECTIVES: The goal of this study was to investigate relationships among SES, psychological stress, and immune processes implicated in asthma. METHODS: Thirty-seven children ages 9 to 18 years, physician-diagnosed with asthma, and 39 healthy children participated. Families were interviewed about chronic life stress, perceptions of threat, and SES. Blood samples were drawn from children to assess stimulated production of cytokines implicated in asthma (IL-4, IL-5, IL-13) and eosinophil counts. RESULTS: In children with asthma, lower SES was associated with heightened production of IL-5 and IL-13 and higher eosinophil counts (P values < .05). Lower SES also was associated with higher chronic stress and perceived threat (both groups: P values < .05). Higher levels of stress and threat perception were associated with heightened production of IL-5 and IL-13, and higher eosinophil counts in children with asthma (P values < .05). Statistical mediation tests revealed that chronic stress and threat perception represented statistically significant pathways between SES and immune processes in children with asthma (P values < .05). In healthy children, associations were in the opposite direction from the asthma group, though generally not significant. CONCLUSION: This is one of the first studies to document empirically a psychobiological explanation for the epidemiologic relationship between low SES and poor asthma outcomes. CLINICAL IMPLICATIONS: Associations among SES, psychological stress, and immune pathways suggest that the experience of stress, particularly among lower SES children, has implications for childhood asthma morbidity.