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Growth And Development Of The Western Harvest Mouse, Reithrodontomys Megalotis Megalotis, Gary H. Richins, H. Duane Smith, Clive D. Jorgensen

Great Basin Naturalist

Growth rates, gestation period, litter size, reproductive age, sex ratios, and development were studied on 198 litters of Reithrodontomys megalotis megalotis (Baird). Growth was characterized by several standard skull and body measurements and was partitioned into four phases of 1–3, 4–12, 13–22, and 23–70 days. Growth was best described by measurements of tail length, ear length, and dried eye-lens weight. Reproductive activity began as early as 38 days for females and 59 days for males. The gestation period was 22 days, and the mean litter size was 3.83 (range 1–7). Sex ratio was 53.49 percent males to 46.51 percent females. …

Studies On The Tolerance Of Aquatic Insects To Low Oxygen Concentrations, Arden R. Gaufin, Robert Clubb, Robert Newell

Great Basin Naturalist

Acute, short-term (96-hour) tests were conducted to determine the relative sensitivity of low oxygen concentrations to 20 species of aquatic insects. In addition, the longer-term effects of low oxygen levels on the survival, molting, growth, and emergence of 21 species were studied. This paper encompasses work conducted at the University of Montana Biological Station from 1968 to 1970 and at the University of Utah from 1966 to 1972.

An evaluation of the average minimum dissolved-oxygen requirements of the different groups of aquatic insects tested indicates that the mayflies are the most sensitive, that the stoneflies are next, and that the …