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Bactrocera tryoni (Froggatt) and Bactrocera neohumeralis (Hardy) are sibling fruit fly species that are sympatric over much of their ranges. Premating isolation of these close relatives is thought to be maintained in part by allochrony—mating activity in B. tryoni peaks at dusk, whereas in B. neohumeralis , it peaks earlier in the day. To ascertain whether differences in pheromone composition may also contribute to premating isolation between them, this study used solid-phase microextraction and gas chromatography-mass spectrometry to characterize the rectal gland volatiles of a recently collected and a more domesticated strain of each species. These glands are typical production sites and reservoirs of pheromones in bactrocerans. A total of 120 peaks were detected and 50 were identified. Differences were found in the composition of the rectal gland emissions between the sexes, species, and recently collected versus domesticated strains of each species. The compositional variation included several presence/absence and many quantitative differences. Species and strain differences in males included several relatively small alcohols, esters, and aliphatic amides. Species and strain differences in females also included some of the amides but additionally involved many fatty acid esters and 3 spiroacetals. While the strain differences indicate there is also heritable variation in rectal gland emissions within each species, the species differences imply that compositional differences in pheromones emitted from rectal glands could contribute to the premating isolation between B. tryoni and B. neohumeralis. The changes during domestication could also have significant implications for the efficacy of Sterile Insect Technique control programs. [ABSTRACT FROM AUTHOR]

A device was developed to monitor rectal temperature automatically in cattle for application in research settings. Compared with manual measurement of rectal temperature, this device decreases labor and time requirements and allows data collection without the influence of animal handling or restraint. The device consists of a custom-fabricated aluminum tail harness that supports an indwelling rectal temperature data logger. Materials cost approximately US $300 per unit, and units are completely reusable. Use of this device would increase the conditions under which accurate rectal temperature measurements can be obtained in experiments with cattle. [ABSTRACT FROM AUTHOR]

Tyrian purple is a dye used in antiquity and is a natural product of marine molluscs of the family Muricidae. Bioactive precursors of Tyrian purple occur in the hypobranchial gland, reproductive glands and egg masses of muricids, such as Dicathais orbita. Histomorphological examination of the hypobranchial–gonoduct complex (rectum and hypobranchial, capsule, albumen and rectal glands) was conducted to provide the first description of the hypobranchial gland in D. orbita and to determine a mechanism for the transfer of Tyrian purple precursors to the gonoduct and ultimately to the egg masses. Seven secretory cell types were identified in the hypobranchial epithelium of D. orbita, which can be broadly classified into cells containing mucoproteins and acidic sulphated mucopolysaccharides. Three secretory cells new to the Muricidae were identified, along with two cell types that appear to be associated with synthesis of Tyrian purple. A subepithelial vascular sinus surrounding the rectum and rectal gland occurs between the hypobranchial gland and gonoduct. Examination of this region failed to reveal a direct anatomical mechanism for the transfer of precursors to the gonoduct. However, biochemical similarities in secretions from the hypobranchial, capsule and albumen glands suggest that the synthesis of precursors within the gonoduct may be possible. [ABSTRACT FROM PUBLISHER]

The effect of breed [Creole (CR) vs. Large White (LW)] on performance and physiological responses during acclimation to high ambient temperature was studied in 2 experiments involving 24 (12/breed) growing pigs each. Pigs were exposed to 24°C for 10 d (d -10 to -1) and thereafter to a constant temperature of 31°C for 16 d (d 1 to d 16) in Exp. 1 and for 20 d (d 1 to d 20) in Exp. 2. For both experiments, the temperature change was achieved over 4 h on d 0. The first experiment began at 105 d of age, and the average BW of CR and LW pigs was 36.6 ± 2.5 kg and 51.7 ± 3.0 kg, respectively. The second experiment was designed to compare both breeds at a similar BW (about 52 kg on d 0). Pigs were individually housed and given ad libitum access to feed. At 24°C, ADG was lower (P <0.01) in CR than in LW (602 vs. 913 g/d and 605 vs. 862 g/d in Exp. 1 and 2, respectively), but the AIDFI was not affected by breed (190 and 221 g·d-1·kg-0.60 in Exp. 1 and 2, respectively). Short-term thermoregulatory responses during the 4-h transition from 24 to 31°C (d 0) were analyzed according to a linear plateau model to determine the break point temperature, above which rectal temperature (RT), cutaneous temperature (CT), and respiratory rate (RR) began to change. The CT increased linearly with temperature increase (0.22°C/°C) and was less (P < 0.05) in CR than in LW (by -0.3°C on average). In both experiments, the break point temperature for RT was not affected by breed (27.6°C on average), whereas for RR it was greater (P < 0.05) in CR than in LW (27.5 vs. 25.5°C, P < 0.01). On average, ADFI declined by about 50 g·d-1·kg-0.60 from d -1 to d 1 (P < 0.01), and thereafter at 31°C, it gradually increased (23 g·d-1kg-0.60; P < 0.05), suggesting an acclimation to high exposure. This response was not influenced by breed. After the day that marked the beginning of the acclimation response (i.e., the threshold day), RR, CT, and RT declined over the duration of exposure to 31°C (P < 0.05) in both experiments. During this period, RT and CT were less in CR than in LW pigs (39.6 vs. 39.9°C and 37.9 vs. 38.2°C, respectively; P < 0.05), whereas RR was not affected by breed. The threshold day at which RT began to decline was less in CR than in LW pigs (0.18 vs. 1.17 d and 0.39 vs. 0.93 d in Exp. 1 and 2, respectively; P < 0.05). In conclusion, this study suggests that short- and long-term physiological reactions during heat acclimation differed when CR and LW pigs were compared at the same age or BW. [ABSTRACT FROM AUTHOR]

A total of 179 lactations obtained on 71 multiparous sows [30 Creole (CR) and 41 Large White (LW)] between June 2001 and July 2004 were used to determine effects of breed (CR vs. LW) and season (hot vs. warm) in a tropical humid climate on performance during a 28-d lactation period. Mean daily ambient temperature was greater during the hot season than during the warm season (26.0 vs. 23.8°C), and relative humidity was similar in both seasons (85% on average). For both breeds, ADFI was reduced (-700 g/d, P < 0.01), sow BW loss was greater (17 vs. 12 kg, P < 0.01), and piglet growth was reduced (197 vs. 210 g/d, P < 0.05) during the hot vs. the warm season. At farrowing, LW sows were heavier (255 vs. 186 kg, P < 0.01) and had less backfat (21 vs. 40 mm, P < 0.01) than CR sows. The growth rate of CR piglets was lower than that of LW piglets (192 vs. 215 g/d, P < 0.01). A breed x season interaction was observed (P < 0.05) for ADFI and sow BW loss. During the hot season, the reduction of ADFI was more pronounced in LW than in CR sows (-910 vs. -470 gld). Regardless of the season, BW loss of CR sows remained constant (14.2 kg), whereas it increased during the hot season for LW sows (10 kg). The weaning-to-estrus and the weaning-to-conception intervals were not affected by breed or season and averaged 4.8 and 6.1 d, respectively. The rectal temperature was greater (0.3°C) during the hot season than during the warm season and greater in LW than in CR sows (39.1 vs. 38.8°C, P < 0.10). This study confirms the negative effect of hot season in a tropical humid climate on performance of lactating sows and that breed can have a significant effect on lactation performance. The results also suggest that CR sows are more heat tolerant than LW sows. [ABSTRACT FROM AUTHOR]