不同温度、土壤含水量及日光照时数对棉露尾甲虫(Haptoncus luteolus (Erichson))生长发育的影响

在5,10,15,20,30℃等5种温度、10%,20%,30%等3种土壤含水量和8,12,16h等3种日光照时数共45个处理组合条件下,以丝瓜花作为饲料研究了3个因素对棉露尾甲生长发育的联合作用。结果表明:适合于卵生长发育的处理组合为25～35℃、10～15%和12～16h,其中最佳处理组合为30℃、10%和12h,在此组合条件下,卵发育历期为0.8d,孵化率为93.3%;适合于幼虫及蛹生长发育的处理组合为:25～30℃、10～15%和12～16h,其中最佳处理组合分别为30℃、10%、12h和30℃、10%、8h,在此组合条件下,幼虫历期、存活率和蛹历期、羽化率分别为5.0d、85.7%和2.2d、83.3%。在三元二次回归模型中,卵、幼虫、蛹和整个未成熟期(卵至蛹的历期)发育进度最快时的处理组合分别为27.5℃、10%、8h,30℃、20%、12h,32.5℃、10%、16h和30℃、10%、16h;此时理论最短历期分别为0.8、4.4、1.4d和7.3d。     

Photoperiodic,thermal and trophic responses of a predatory ladybird Cheilomenes propinqua

Large geographic range, wide habitat specificity and broad range of prey (including a number of pests of protected crops) suggest that a predatory ladybird Cheilomenes propinqua can be considered as potential agent for biological control in greenhouses. We investigated the influence of day length (10, 12 and 14 hr), temperature (20 and 24°C) and diet (the green peach aphid Myzus persicae and eggs of the grain moth Sitotroga cerealella) on the rate of maturation, fecundity and induction of reproductive diapause in C. propinqua females of a laboratory population originated from Alexandria, Egypt. The proportion of diapausing females (i.e. those with poorly developed ovaries and well-developed fat body) varied from 5% to 70% being higher at short day, low temperature and feeding on the grain moth eggs. This diapause, however, was not very stable: more than 20% of females kept under diapause-inducing conditions started to lay eggs during 110 days, although their pre-oviposition period was about 5 times longer than that of females which matured at the same temperature but at the long day and on the natural diet. Although not very stable, reproductive diapause significantly increased survival of starving females. Such a short-term reproductive diapause can be considered as an adaptation to mild and short-term subtropical winter. The results of our study suggest that C. propinqua mass rearing will be more intensive at the combination of high temperature, natural food (aphids) and long day (14 hr), whereas individuals intended for long-term storage should be reared under moderate temperature (20°C) and short-day (10 hr) conditions and should be fed on factitious food (the grain moth eggs).     

Life history of Galerucella nymphaeae and implications of reproductive diapause for rearing univoltine chrysomelids

Abstract. Galerucella nymphaeae L. , a chrysomelid that feeds on Lythrum spp., water lily and water chestnut, is closely related to two European species that were recently introduced into North America for biological control of L.salicaria , purple loosestrife. To develop a paradigm for continuously rearing these and other univoltine chrysomelids, we conducted field and laboratory studies on G. nymphaeae's development , reproduction and diapause.
A high incidence of reproduction without diapause occurred when fourth instars, pupae, and adults (held as pairs) experienced very long daylengths (LD18:6 h), i.e. longer than those G.nymphaeae encounters in nature. Under similar photoperiodic conditions, adults maintained in groups showed a significantly higher rate of reproductive diapause than those held as pairs. Females laid three to seven egg masses/week, and the size of egg masses varied between nine and nineteen eggs. During their reproductive lifetimes, individual females showed a highly significant propensity to lay a consistent number of eggs/egg mass.
After diapausing under short daylengths and low temperature (LD 10:14h, 5C), adults transferred to long days (LD 18:6h at 21C) had high rates of diapause termination and postdiapause oviposition. In contrast, those transferred to short daylengths (LD 10:14h at 21C) had low rates of reproduction.
Laboratory-derived heat-degree models accurately predicted egg and pupal, but not larval, development in the field. In nature, most females in the summer generation entered reproductive diapause without ovipositing; a small proportion of females that emerged relatively early (by mid June) oviposited before entering diapause. The overwintering population consists of adults from the first-generation and a small number from the second generation.     

Effects of lighting programs on onset of the ovulatory season in mares

Using 240 pony mares, lighting regimens were tested for their efficiency in hastening the onset of the ovulatory season. The mean number of days from January 1 to first ovulation was used as the end point. No advantage was gained by beginning a fixed lighting regimen ($\text{15.5L}\text{8.5D}$, hours light/hours dark) November 1 (66 ±8) versus December 1 (65 ±9), but beginning on January 1 was less efficient (98 ±8; controls, 132 ±5; P<0.05). In another experiment, daily three-hour interruptions of either the light phase (67 ±10) or the dark phase (71 ±11) did not significantly retard the effectiveness of a fixed regimen of $\text{15L}\text{9D}$ (54 ±5; controls, 142 ±6). A $\text{15L}\text{9D}$ regimen every other day (natural day length on alternate days) resulted in an interval (85 ±7) that was shorter (P<0.05) than for the controls and longer (not significant) than for the daily $\text{15L}\text{9D}$ regimen. When used with natural day length, a one-hour pulse of light in the evening (15 hours after sunrise) was not effective (141 ±6); a one-hour pulse in the morning 9.5 hours after sunset) was only partially effective (117 ±6). In another experiment, the interval was reduced (P<0.05) in a group with one hour of light fixed at 4:00 a.m. with natural day length (85 ±8; $\text{15L}\text{9D}$, 75 ±7; controls, 126 ±9). Results indicated that a fixed one-hour pulse of light at 4 a.m., used with natural day length, may provide an acceptable level of stimulation.     

Effect of temperature and photoperiod on the growth of the embryonic dogfish, Scyliorhinus canicula

Photoperiod has no effect on the growth of embryonic dogfish. Conversely, developmental rates are highly susceptible to temperature variation. Embryos maintained at 16°C grew faster and ecloded earlier than those maintained at 10°C. Increased temperature had no effect on size at eclosion.     

Photoperiodic regulation of the development of winged gynoparae in the aphid, Aphis fabae

ABSTRACT. In uncrowded rearing conditions, determination of the winged gynopara of the Aphis fabae Scopoli is dependent upon both pre- and postnatal short days (LD 12:12). Extension of the photophase to produce longday (LD 16:8) conditions localized on the head or abdominal region, showed that during the early larval instars of the parent generation (G1) there is a maternally-controlled induction of gynoparae. However, during later stages of embryonic development the presumptive gynoparae respond directly to photoperiod through the mother's abdominal wall. During early postnatal development, presumptive gynoparae (G2) remain sensitive to photoperiodic conditions; the photoperiodic receptors lie in the head. These results are discussed with respect to possible endocrine mediators of this photoperiodically controlled polymorphism.     

Maintenance and termination of reproductive dormancy in an Australian stink bug, Biprorulus bibax

Reproductive dormancy in female Biprorulus bibax Breddin sampled during March-October in Southern New South Wales was terminated by exposure to 25°C under long (15h) and short (10h) photoperiods. 27% of individuals collected during March-May failed to oviposit under short days. Pre-oviposition period under short photoperiod was greates during March-June (22.4–61.7 d) and shortest during July-October (4.2–14.4 d). Under long photoperiod it was greatest in April and May (20.1–22.3 d) and shortest during June-October (4.9–16.6 d). Longevity ranged from 39.8–89.0 d, with longest lived females being collected in June and held under short days. Fecundity ranged from 51.6–164.4 and was greatest in individuals collected in June-July and held under short days. In females held under long days fecundity was greatest in March and lowest in May. These data indicate that female B. bibax pass the winter in a photoperiodically maintained reproductive diapause.     

The combined effect of photoperiod and temperature on the calling behaviour of the true army worm, Pseudaletia unipuncta

ABSTRACT. Pseudaletia unipuncta (Haw.) (Lepidoptera: Noctuidae) virgin females, maintained at either 10 or 25d?C under LD 12:12 or 16:8 h, started calling at different ages. For a given photoperiod, calling was initiated 11 days later at 10d?C than at 25d?C, while for a given temperature, calling at LD 12:12 h was 3–4 days later than at LD 16:8 h. At 10d?C 50.8% of females did not call within 35 days at LD 12:12 h compared with 30.8% at LD 16:8 h. Calling started earlier in the scotophase at 10d?C than at 25d?C and at LD 16:8 h than at LD 12:12 h. Under all treatments calling generally advanced on successive nights. The time elapsed between the mean onset time of calling and the mid-scotophase was relatively constant under both photoperiod conditions at 25d?C, but at 10d?C was more variable. The mean time spent calling increased significantly with calling age but did not differ significantly between the four experimental conditions tested. Older (15 days) females transferred from 10d?C, LD 16:8 h to 25d?C at either LD 163 or 12:12 h, required less time to initiate calling than younger (5 days) ones. Those transferred from 10d?C, LD 12:12 h took the same time, regardless of their age at the time of the transfer. Females experiencing either a decrease or increase in daylength as well as a temperature increase, required respectively more or less time to initiate calling, compared with individuals that only experienced an increase in temperature. If temperature was the only parameter changed females that initiated calling soon after the transfer immediately adjusted their calling periodicity to prevailing conditions. When both temperature and photoperiod were altered, it took several days before calling periodicity adjusted to the new regime. The ecological implications of temperature and photoperiodic conditions on the possible autumn migration of P. unipuncta are discussed.     

Regulation of pheromone production by female pink bollworm moths Pectinophora gossypiella (Sanders) (Lepidoptera: Gelechiidae)

Abstract. We present in this study data which indicate that there is a diel periodicity in the pheromone production of the pink bollworm moth Pectinophora gossypiella (Sanders) (Lepidoptera: Gelechiidae) but that it is not well defined. Moreover the control mechanism of pheromone production differs somewhat from that reported for other moths. No pheromonotropic response was obtained when photophase females were injected with synthetic Helicoverpa zea pheromone biosynthesis activating neuropeptide (Hez-PBAN). After decapitation for 24 h, Hez-PBAN did not induce pheromonotropic activity above control levels, which themselves remained relatively high. No effect on pheromone production was observed after treatment with the non-steroidal ecdysone agonist (RH5999). Decapitation for 72 h resulted in a significant drop in the control levels of pheromone titres. After decapitation for 72 h, stimulation by injections of Hez-PBAN and pink bollworm head extracts was observed. In addition, an enhancement of the PBAN stimulation was observed when combined with severance of the ventral nerve cord before injection. On the other hand, pink bollworm head extracts did not cross-react with Hez-PBAN antiserum in a radioimmunoassay, indicating that the pheromonotropic factor present is sufficiently different from Hez-PBAN and does not recognize the antigenic binding sites. In studies using isolated abdomen and pheromone gland cultures in vitro , no stimulation of de novo pheromone biosynthesis was observed but a 3-fold increase in the de novo fatty acid biosynthesis was detected in pheromone gland cultures.     

Effects of diet, photoperiod and temperature on the postdiapause reproduction in the cabbage bug,Eurydema rugosa

InEurydema rugosa Motschulsky (Heteroptera: Pentatomidae), the type of food supplied (i.e. seeds or leaves of the brown mustard,Brassica juncea Hemsel) and photoperiod, which control the induction of adult diapause, do not play a role in the initiation of reproduction after overwintering. A temperature above 13.2°C was required to start reproduction. After its initiation, however, short-day conditions on seeds induced diapause again in some adults. Although a diet of seeds under long-day conditions, in common with short-day conditions, induced diapause in young adults (Numata & Yamamoto, 1990), it did not reinduce diapause in adults after overwintering. Thus,E. rugosa that had overwintered became sensitive to diapause-inducing photoperiod again but not to dietary factors.