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Social parasitism in insects has raised major questions in evolutionary biology, firstly in terms of adaptations that parasites use to circumvent host defenses and, secondly, in terms of whether social parasites have arisen via allopatric or sympatric speciation. Here, we raise a third and major evolutionary issue: a priori considerations suggest that social parasites have much smaller effective population sizes ( Ne) than their hosts, and should therefore have much slower rates of evolution than their hosts. The evolutionary arms race should therefore be weighted in favor of host species, raising the question of how social parasites have been able to persist over evolutionary time? Very few studies, however, have actually estimated the relative sizes of Ne for social insects and their social parasites, and therefore the dimensions of unequal host-parasite evolutionary rates are unknown. Here, we use extensive samples of allodapine bee host species and their inquilines from two localities over multiple years to gage their relative Nes. We show that inquiline species have Nes that are about an order of magnitude lower than their hosts, so explaining the evolutionary persistence of social parasitism poses a major puzzle for evolutionary biology. We propose several hypotheses that may be able to address this puzzle and discuss how they could be evaluated. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of calcium (Ca) and magnesium (Mg) injection around mating on skewing lamb sex ratio in ewes. Thirty cycling multiparous Kurdish × Romanov ewes were divided into two groups (15 per group) based on age and body weight (BW). Animals were received either 20 mL of solution (CaMg) or 20 mL of sterile water (Control) subcutaneously every 7 days from 28 days preto 7 days post-mating. Each mL of CaMg solution contained 400 mg of Ca borogluconate and 22 mg of Mg hypophosphate, which provided 30.4 mg of Ca and 2.04 mg of Mg. Ewes in CaMg group tended to had lower body condition score (BCD) at the day of controlled internal drug release (CIDR) removal (2.79 vs. 2.69; P=0.09) and its change from beginning of experiment to CIDR removal (0.21 vs. 0.04; P=0.06) than control group. The CaMg injection increased plasma insulin (13.2 vs. 11.33 μIU/mL), Ca (9.13 vs. 8.30 mg/dL), Mg (3.66 vs. 3.33 mg/dL), Na (188.83 vs. 175.73 mEq/L) and glucose (56.94 vs. 50.07) concentrations at the day of CIDR removal and Ca (8.87 vs. 8.03 mg/dL) at the day of estrous and mating compared to control group (P<0.05). Lower estradiol (E2) + testosterone to progesterone (P4) ratio at the day of estrous and mating (102.87 vs. 135.67) was observed in ewes received CaMg injection compared to other group (P<0.05). Injection of CaMg solution had no significant effect on lamb sex ratio (P>0.05), although proportion of female lambs (68.18 vs. 56.52%) was numerically higher in ewes of the CaMg group than control group. These results indicated that there was a potential for skewing the sex ratio of lambs toward females when CaMg solution was injected subcutaneously during mating. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of diets containing roasted soybean (R), extruded soybean (E) or their combination (RE) on dairy cow performance and milk fatty acid (FA) profile. Nine multiparous lactating Holstein cows (680 ± 25 kg BW; 90 ± 10 DIM; means ± SD) were randomly assigned to a triple 3 × 3 Latin square design. Dry matter intake (DMI), apparent nutrient digestibility, milk yield, composition and FA profile and efficiency of nitrogen (N) utilization for milk production were measured. Cows fed R and RE had higher 4% fat corrected milk (FCM) yield and DMI compared to those fed the E (P<0.05). The efficiency of 4% FCM production per unit of DMI was not influenced by experimental diets (P>0.05). Experimental diets had no effect on milk fat and protein concentrations and nutrient digestibility (P>0.05). Milk fat concentrations of vaccenic acid (VA; C18:1 trans-11) and conjugated linoleic acid (CLA; C18:2 cis-9, trans-11) were higher for cows fed with RE compared to other groups (P<0.05). We concluded that cows fed with RE had similar milk production and fat content compared to those fed with R and a similar beneficial milk FA profile compared to those fed with E. Thus, feeding a diet with RE improved the quality and quantity of dairy cow milk. [ABSTRACT FROM AUTHOR]