Evaluation of Pit-trap Transects With Varied Trap Spacing in a Northern Michigan Forest

The study compared effects of four distances between traps (range 0.5-4.0 m) on arthropod captures. Twelve traps were aligned in each of four transects, and 20 samples. trap were obtained during summer and fall in a northern Michigan deciduous forest. Catches proved to be unaffected by trap spacing. Rather, they reflected local within-site differences in abundance of dominant species

The Life Cycle Relative to Temperature of Protaphorura Armatus (Tullberg) (Collembola: Onychiuridae), a Parathenogenetic Species

Apparent parthenogenetic reproduction in Collembola has sometimes been attributed to accidental transfer of spermatophores with the food material from one culture to another (Schaller, 1953; Mayer, 1957). Conclusive evidence of parthenogenesis has only in recent years been accumulated for a number of species of Collembola, of which some were found in field populations consisting entirely of females (Choudhuri, 1958; Huther, 1961; Marshall and Kevan, 1962; Petersen, 1965; 1971 ; Snider, 1973). In Onychiuridae, parthenogenesis is apparently quite common. Onychiurus parthenogeneticus Choudhuri and Tullbergia krausbaueri (Bomer) undoubtedly reproduce in the absence of males (Choudhuri, 1958; Hale, 1966; Petersen, 1971); so does Tullbergia granulata Mills, where individuals reared in isolation from the time of hatching invariably lay viable eggs (unpublished observations). Large females of Onychiurus procampatus Gisin 1956 breed through a form of thelytokous parthenogenesis (Hale, 1964). The size groupings found in O. procarnpatus (two sizes of females and only small males) were also observed in O. firnatus Gisin 1952 and O. quadriocellatus Gisin 1947 and may indicate the existence of both parthenogenetic and sexually reproducing forms in these species (Hale, 1964). Recent laboratory observations on Protaphorura armatus (Tullberg) revealed that this species too reproduces parthenogenetically. The present study was undertaken to investigate the effect of temperature on the biology of the species

Influence of Exercise Environment on Stress and Affect in Sedentary Adults: A Comparison of Indoor and Natural Environments

The national need for increased physical activity, especially among sedentary populations, has been well documented. The need now is for fitness programs to be more effective at encouraging individuals to adopt and maintain a physically active lifestyle. This study investigated the relationship between exercise environment, stress, affect, and Nature Relatedness. Because stress reduction has been seen as a benefit of being exposed to nature, stress and affect were assessed in sedentary adults at the beginning and end of short walks in an outdoor and indoor environment in an effort to determine which environment had the greater ability to reduce stress. Stress and affect were measured using salivary cortisol concentration and alpha-amylase activity, as well as surveys and questionnaires. Additionally, the link between Nature Relatedness and environmental preference was assessed. Ultimately, our results indicated that this population expressed a preference for exercising in the outdoor environment over the indoor environment

The Life History of Folsomia Candida (Willem) (Collembola: Isotomidae) Relative to Temperature

The parthenogenetic mode of reproduction in Collembola, although frequently questioned in the past (Schaller, 1953; Mayer, 1957; Falkenhan, 1932), has only recently been recorded and confirmed for several species; Onychiutus parthenogeneticus Choudhuri (Choudhuri, 1958), Folsomia candida (Willem) (Goto, 1960; Marshall and Kevan, 1962; Green, 1964; Husson and Paldvody, 1967), Folsomia cavicola Cassagnau and Delamare (Goto, 1960), Tullbergia krausbaueri (Bomer) (Hale, 1966; Petersen, 1971), and Isotoma notabilis Schaffer (Petersen, 1971). Sex-ratios in populations of the above cited species are often unknown. Existing data indicate that the composition of a population may vary with the geographical distribution of the species. Populations of Folsomia candida (Willem), known to be bisexual in England (Goto, 1960), have been found so far to consist entirely of females in Canada (Sharma and Kevan, 1963a) and in Michigan (Snider, 1973). Similar to I. notabilis and T. krausbaueri (Petersen, 1971), investigations throughout the year and over larger geographic areas are necessary before northern USA and Canada F. candida may be labeled as obligatory parthenogenetic. Snider (1973) recorded in detail the life cycle of F. candida at 21°C. The present study provides information on the influence of temperature on the bionomics of the species

Observations of attenuation at 20.6, 31.65 and 90.0 GHz: Preliminary results from Wallops Island, VA

Ground based radiometric observations of atmospheric attenuation at 20.6, 31.65, and 90.0 GHz were made at Wallops Island, Virginia during April and May 1989. Early results from the analysis of the data set are compared with previous observations from California and Colorado. The relative attenuation ratios observed at each frequency during clear, cloudy, and rainy conditions are shown. Plans for complete analysis of the data are described