Summary 1. A series of experiments was conducted to measure the impact of plant genotype, plant growth rate, and intraspecific competition on the oviposition preference and offspring performance of the host races of Eurosta solidaginis (Diptera: Tephritidae), a fly that forms galls on Solidago altissima and Solidago gigantea (Asteraceae). Previous research has shown that both host races prefer to oviposit on their own host plant where survival is much higher than on the alternate host plant. In this study, neither host race showed any relationship between oviposition preference and offspring performance in choosing among plants of their natal host species. 2. The larval survival of both host races differed among plant genotypes when each host race oviposited on its natal host species. In one experiment, altissima host race females showed a preference among plant genotypes that was not correlated with offspring performance on those genotypes. In all other experiments, neither the altissima nor gigantea host race demonstrated a preference for specific host plant genotypes. 3. Eurosta solidaginis had a preference for ovipositing on rapidly growing ramets in all experiments, however larval survival was not correlated with ramet growth rate at the time of oviposition. 4. Eurosta solidaginis suffered high mortality from intraspecific competition in the early larval stage. There was little evidence, however, that females avoided ovipositing on ramets that had been attacked previously. This led to an aggregated distribution of eggs among ramets and strong intraspecific competition. 5. There was no interaction among plant genotype, plant growth rate, or intraspecific competition in determining oviposition preference or offspring performance.

The hypothesis was tested that selection on the basis of family means for increased survival and hen-housed egg production, when sisters with intact beaks were kept together in multiple-bird cage, would cause adaptive changes in behavior. Specifically, it was posited that beak-inflicted injuries causing cannibalistic mortality and feather loss and damage would be reduced. Body weight effects were not predicted, but were examined. Three stocks were compared; the Selected (S), representing the seventh generation of selection, the Randombred Control (C) from which S was derived, and a commercial stock (X), known to be highly productive and peak-trimmed by commercial producers. Pullets were placed in single-bird (1H) as well as in 12-hen (12H) cages using a completely randomized block experimental design. Mortality from beak-inflicted injuries differed among stocks in total hens lost (P < 0.005). Of 576 per stock in 12H cages 287, 128, and 46 replacements were used from 17 to 44 wk in X, C, and S, respectively, to maintain group size. The C and S hens also differed from 44 to 59 wk and 17 to 59 wk. X hens were not included in comparisons of mortality beyond 44 wk. Relative incidence of mortality caused by vent-cloacal injuries differed with X > C = S (P < 0.005 for X vs C and S). For cages with > or = 1 cannibalistic death, X had twice (P < 0.025) and C 1.6 times (P < 0.10) as many with repeated losses as S. Means and variances of feather scores were different for 1H vs 12H cages, ages, and genetic stocks. Greater variances were observed in 12H cages and among older birds. Within 1H units, genetic stocks did not differ in general, but in 12H cages X and C were always more variable than S. In 12H cages, mean feather scores and body weights were decreased and S hens had better feathering than either C or X. The evidence supported the hypothesis.

Extrinsic, host-associated environmental factors may influence postmating isolation between herbivorous insect populations andrepresent a fundamentally ecological cause of speciation. We investigated this issue in experiments on hybrids between the host races of Eurosta solidaginis, a fly that induces galls on the goldenrods Solidago altissima and S. gigantea. To do so, we measured the performance of parental host races and their hybrids on five genotypes of S. gigantea and nine genotypes of S. altissima to test hypotheses about how variation in plant genotype affects performance (i.e., fitness) and potentially influences gene flow between these host races. We found that rates of gall induction and of survival to adult emergence by hybrid larvae were significantly lower than those of both parental host races on both host species, adding support to the hypothesis that there is partial postmating isolation between the host races. Hybrid flies significantly varied in their performance across plant genotypes of both host species. A significant interaction between the effects of plant genotype and mating treatment (parental vs. hybrid crosses) on larval performance indicated that the relative suitability of particular plant genotypes differed between the parental host races and their hybrids. These patterns illustrate a poor correspondence between optimal parental and hybrid environments, consistent with the hypothesis that these host races are partially isolated due to extrinsic (ecological) factors. Based on these findings, we discuss the possibility that plant genotypes in which hybrid performance is high can facilitate hybridization and gene flow between partially reproductively isolated populations of herbivorous insects, thus affecting the dynamics of ecological speciation.

We studied research published between 1971 and 1983 on the effects of crowding and cage shape on performance of layers. Three density categories were selected for analysis based on cage floor area per hen: 1) low, ranging from 432 to 561 cm 2 , averaging 516 cm 2 ; 2) medium, ranging from 3 55 to 426 cm 5 , averaging 387 cm 2 ; and 3) high, ranging from 271 to 348 cm 2 , averaging 310 cm 2 . Comparisons were made of exactly reversed, deep vs. shallow cages and not exactly reversed, deep vs. shallow cages.Although direct comparisons of all three densities were seldom available within studies, the overall results suggest a curvilinear relationship with performance traits decreasing more rapidly at higher densities. Reducing floor space per hen from an average of 387 cm 2 (medium) to 310 cm 2 (high) reduced eggs per hen housed by 16.6 (P<.001), increased mortality 4.8% (P<.001), decreased feed consumption 1.9 g/hen/day (P<.05), and increased feed consumption per dozen eggs by 68 g (P<.001). Data from the comparison of 516 cm 2 (low) vs. 387 cm 2 (medium) showed the increase in crowding reduced egg production by 7.8 eggs per hen housed (P<.01), increased mortality by 2.8% (P<.05), and decreased feed consumption/hen/day by 4.3 g (P<.05). Egg production was significantly (P<.05) affected by cage shape. Hens in shallow cages produced 5.8 more eggs per hen housed than those in deep cages. (Key words.-crowding, cage shape) 1985 Poultry Science 64:238-242

Beef longissimus muscle steaks were broiled or roasted to 7 internal temperatures. Mouth-filling-blend and browned flavor increased, whereas bloody-serumy, metallic, and sour flavors and juiciness decreased with increased internal temperature. Roasted muscles had flavor characteristics more like muscle cooked to lower internal temperatures than broiled. Protein denaturation, as indicated by differential scanning calorimetry, appeared to be mostly complete after muscle samples were heated to 80" C. Visual color change occurred between 55" and 65" C, between 6.5" and 75" C, and between 75" and 80" C. HunterLab a values decreased and reflectance readings at 547 nm increased significantly between 75" and 80" C. Instron shear and compression and pH values did not vary significantly.