A genetic analysis of photoperiodic reproductive diapause in Drosophila triauraria

Abstract. Recombinant inbred lines were produced from hybrids between diapausing and non-diapausing strains of Drosophila triauraria Bock & Wheeler by twenty generations of full-sib mating. The analysis of these inbred lines suggests that the difference in the photoperiodic response between the original diapausing and non-diapausing strains is due to genes at three or four loci and at least one of these loci is located on the X chromosome. The original diapausing strain and two inbred lines exhibited circadian peaks when subjected to the Nanda-Hamner protocol, although they had different critical daylengths. This suggests that critical daylength is modified independently of the circadian oscillation system in this species. On the other hand, diapause duration was correlated with critical daylength among the inbred lines and the original diapausing strain, suggesting that these two traits are under the control of the same genetic system.     

中稻田三种飞虱的捕食性天敌优势种及农药对天敌的影响

对两优0923非防治的中稻田白背飞虱、灰飞虱和褐飞虱与其天敌间的关系,采用灰色关联度法、生态位分析方法,对盆拍法调查的3种飞虱与其捕食性天敌在数量、时间和空间三方面关系进行分析,对每一种天敌对应的关联度、生态位重叠指数和相似性比例等参数标准化后的密切指数相加,按照密切指数值之和大小排序,评判3种飞虱捕食性天敌优势种.并用同样方法分析常规防治田农药对飞虱捕食性天敌的影响,以期为合理施药,科学保护和利用天敌优势种提供科学依据,其结果是,非防治田白背飞虱前三位天敌是条纹蝇虎、草间小黑蛛和锥腹肖蛸;灰飞虱的是八斑球腹蛛、茶色新园蛛和锥腹肖蛸;褐飞虱的是纵条蝇狮、四点亮腹蛛和黑肩绿盲蝽.防治田白背飞虱前三位天敌是条纹蝇虎、草间小黑蛛和锥腹肖蛸;灰飞虱的是拟水狼蛛、四点亮腹蛛和草间小黑蛛;褐飞虱的是黑肩绿盲蝽、拟水狼蛛和四点亮腹蛛.盆拍法的防治田和非防治田之间3种飞虱前三位的相同天敌,白背飞虱完全相同,灰飞虱没有相同天敌,褐飞虱的是黑肩绿盲蝽和四点亮腹蛛.飞虱与天敌在时间和数量关系上,扫网法的防治田和非防治田之间3种飞虱前三位的相同天敌,白背飞虱的是锥腹肖蛸和四点亮腹蛛,灰飞虱完全相同,褐飞虱的是纵条蝇狮和条纹影虎.两种稻田的差异主要是农药杀伤了飞虱,使飞虱数量减少,并对天敌有一定杀伤力,进而影响到天敌的发生规律.非防治田的盆拍法和扫网法之间,3种飞虱前三位相同的天敌,白背飞虱的是锥腹肖蛸,灰飞虱的也是锥腹肖蛸,褐飞虱的是纵条蝇狮.防治田两调查方法结果之间,白背飞虱的是锥腹肖蛸,灰飞虱和褐飞虱前3位天敌中没有相同天敌,其差异主要是两法调查稻株的部位不同所致.     

The effect of temperature and light pulses on the induction of diapause in the Toyama strain of the Indian meal moth, Plodia interpunctella

Abstract.The photoperiodic response in Plodia interpunctella collected at Toyama (36.7°N) was of long-day type and highly sensitive to temperature. The critical photoperiod giving 50% diapause was between 14 and 16 h at 20°C, between 12 and 14 h at 25°C and between 6 and 8 h at 30°C. Effects of night interruption by a 2-h light pulse on the diapause response were examined at 25°C on different background photoperiods ranging from LD 12:12 h to LD 2:22 h. Percentage diapause was very low when the middle portion of dark period was interrupted, so that U- or V-shaped response curves were obtained with background scotophases longer than 12 h. In these curves, the descending slopes were less steep than the ascending slopes. The critical dark period measured from dusk to an interrupting light pulse was about 1.5 h longer than the critical dark period ( c . 10 h) in the normal photoperiodic response. The critical dark period from the interrupting light pulse to dawn, on the other hand, was not parallel to dawn but shorter than the normal critical period in LD 12:12 h and LD 10:14 h and longer than that in LD 7:17 h to LD 4:20 h, indicating that the priming effects of the light pulse might be under the influence of the photophase.     

Differentiation in life cycle of sympatric populations of two forms of Hyphantria moth in central Missouri

Wing patterns of Hyphantria adult male moths collected in central Missouri were examined throughout the breeding season. Three major peaks of adult flight were observed: the first peak consisted mainly of adults with spotted wings, while the second and third peaks consisted of immaculate adults. Black‐headed larvae appeared in the field following the first major peak of moth flight, and red‐headed larvae appeared in the field following the second peak. Sympatric red‐headed and black‐headed forms were collected in the field and subsequently reared on an artificial diet under conditions of 16 h light : 8 h dark (LD 16:8) at 25°C. The larval period of the black‐headed form was shorter than the red‐headed, whereas the pupal period of the black‐headed form was longer than the red‐headed. Pupal development is retarded in some individuals at high temperatures in the black‐headed form. Photoperiodic response curves for pupal diapause were different between the two forms. The critical photoperiod for pupal diapause was 15 h 10 min in the red‐headed form, which was longer than that for the black‐headed form (14 h 40 min). The two forms responded to shifts in photoperiod differently. These developmental responses temporally separate the two forms in the field; the red‐headed and black‐headed forms represent a set of adaptations favoring univoltinism and bivoltinism, respectively. Red‐headed larvae fed mainly at night, while the black‐headed larvae fed without a clear day–night rhythm. Nocturnal feeding in the red‐headed form is adaptive to protection against predation, but fails to fully utilize heat units and thus to produce a second generation.     

Some effects of low temperature on the photoperiodic clock in Drosophila triauraria

Abstract. Prior studies revealed that the photoperiodic clock in Drosophila triauraria operates during the scotophase and the processes measuring scotophase are composed of two phases: the A phase which lasts 6–7 h from the onset of the scotophase and the B phase which follows the A phase. In this study the photoperiodic clock in this species was analysed by low-temperature pulses. Low temperature (5C) or a low-temperature (2C) pulse of 3 or 4 h decreased the induction of diapause when applied during the scotophase, but not when applied within the photophase. The low-temperature pulse showed two maxima of the effect, 0–4 h and 8–10 h after the onset of the scotophase, approximately corresponding to the A and B phases, respectively. It is considered that low temperature retards the time measurement processes operating during these phases. In the period which was rather insensitive to the diapause-preventing action of low temperature, i.e. 5-7h after the onset of the scotophase, substances or stimuli accumulated during the A phase may be converted to information required for operation of the machinery in the B phase. Experiments using a combination of low-temperature and light pulses suggested that low-temperature decreases the sensitivity to light, especially in the B phase.     

Effect of different artificial diets on diapause induction under controlled temperature and photoperiod in the silkworm, Bombyx mori L.

ABSTRACT. Embryonic diapause of the silkworm, Bombyx mori , is generally induced by temperature and photoperiod during the egg stage of the previous generation and not in the larval stage. However, when silkworm larvae are reared on an artificial diet instead of mulberry leaves, their diapause is strongly affected by temperature and photoperiod experienced in the larval stage, with a distinct long-day response for diapause induction. Moreover when larvae which have been reared on artificial diet under long-day condition are fed mulberry leaves even for a short period of time, most of the resultant female adults lay diapause eggs. These results suggest that the photoperiodic response of larvae for diapause induction may be strongly suppressed by some components in mulberry leaves.     

两种杀虫剂对稻田捕食性天敌集团捕食功能的影响

将稻田各类捕食性天敌作为一集团,运用功能法评价了甲胺磷和杀虫双对该集团捕食功能的影响,由于各类捕食性天敌对杀虫剂敏感性的不同,甲胺磷和杀虫双造成的各类天敌的死亡率和残存天敌个体的捕食功能减退率均不同。实验表明,隐翅虫类和狼蛛类对甲胺磷较为敏感,而对杀虫双,肖蛸类最为敏感。杀虫双对隐翅虫类的致死作用及捕食功能影响较小。就集团的捕食功能而言,甲胺磷影响明显大于杀虫双,但在总的功能减退率组分中,甲胺磷致     

A weak tendency to “obligatory” diapause inCoccinella septempunctata from southern Spain

Diapausing adults ofC. septempunctata were collected in November from hibernation quarters in the mountains Sierra de Grazalema in southern Spain. In their progeny, the incidence of non-ovipositing females under long day of 20L∶4D and 25°C was 24%. Thus the tendency to an “obligatory” onset of diapause was much lower than in populations from central Europe and France. The progeny appeared neutral to photoperiod, as a similar low incidence of diapause was also obtained at short day of 12L∶12D and 25°C.     

Adaptive significance of the recurrent photoperiodic response in a spring‐breeding carabid beetle,Carabus yaconinus

Seasonal changes in the photoperiodic sensitivity for reproduction in adults of a spring‐breeding carabid beetle, Carabus yaconinus (Coleoptera: Carabidae), were examined by transferring adults from outdoor to photoperiodic conditions in various seasons. Newly‐emerged adults transferred to the laboratory in September to December showed a long‐day photoperiodic response, but lost photoperiodic sensitivity gradually during winter. In late April, overwintered adults were not sensitive to the photoperiod, with females continuing to have mature eggs under both long‐day and short‐day conditions. In contrast, in late June and late July, the adults were sensitive to the photoperiod, with only those kept under short‐day conditions re‐entering reproductive diapause. This recovery of photoperiodic sensitivity appears to play a definitive role in maintenance of diapause in autumn for adults that have reproduced. The adults collected in late April regained photoperiodic sensitivity in two months even after being kept under unchanged conditions. Therefore, no environmental cue is required for recovery of photoperiodic sensitivity, which apparently recovers with the lapse of time. Our results suggest that the recurrent photoperiodic response is required in long‐living adults of C. yaconinus to regulate the timing of reproduction, and also indicate a difference in photoperiodic sensitivity in summer between overwintered and newly‐emerged adults.     

小麦-油菜邻作对麦田主要害虫和天敌的影响

应用昆虫群落生态学的群落特性分析方法,于2008年和2009年在河北省邯郸市调查了小麦与油菜邻作对麦田蚜虫及主要天敌群落的构成、丰富度和稳定性的影响.结果表明：小麦与油菜田间昆虫群落的组成相似,主要田间害虫为蚜虫,其捕食性天敌包括瓢虫类、草蛉类、蜘蛛类和食蚜蝇,寄生性天敌为蚜茧蜂;两年间田间昆虫群落的组成有一定的变化,但均表现为邻近油菜的麦田蚜虫丰富度最低,捕食性天敌和寄生性天敌的丰富度最高;邻近油菜的麦田昆虫群落、麦蚜亚群落、捕食性天敌亚群落的稳定性高,远离油菜的稳定性低.该模式可以有效保护和利用天敌,增强田间自然天敌对害虫的控制能力.     

Maternal temperature has different effects on the photoperiodic response and duration of larval diapause in blow fly ( Calliphora vicina ) strains collected at two latitudes

Abstract .The blow fly Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae) has a wide distribution across northern and temperate Europe. It has a facultative, maternally-induced larval diapause in response to short days. The photoperiodic response, measured at 15 and 20°C, of two populations was compared. A southern population (originating at 51° N) was sensitive to temperature at all daylengths; the incidence of diapause was greatly reduced at 20°C compared with 15°C. The photoperiodic response of a northern population (from 65° N) was sensitive to temperature only in long days; in short days (< 14 h of light) the response of this strain was identical at each temperature.
Variation in parental photoperiod and temperature were found to affect the duration of larval diapause, indicating a role for maternal effects in diapause intensity as well as incidence. However, the between-strain variation was greater than that within strains, indicating qualitative differences in diapause response. These differences may arise from the ecological conditions at the points of origin of the two strains. The northern strain from the harsher climate has a more intense diapause that follows a relatively temperature-insensitive photoperiodic response. In contrast, the southern strain has a shallow diapause and its photoperiodic response may be overridden by the experience of concurrent high temperature.     

二化螟水稻种群与茭白种群光周期反应的比较

本文报道了用水稻和茭白分别饲养二化螟水稻种群和茭白种群的光周期反应。光周期反应曲线显示,用水稻饲养茭白种群或用茭白饲养水稻种群,无论是在短光照还是在长光照条件下,绝大多数幼虫被诱导进入滞育,丧失了各自原有的光周期反应特性,表明这两个种群已分化到仅适应其本身寄主的程度。用水稻饲养的茭白种群仅有5%～6%的个体化蛹,且其幼虫期较用茭白饲养的延长了15～18天;而用茭白饲养的水稻种群有30%～40%的个体化蛹,其幼虫期与水稻饲养的仅相差3～8天。茭白种群用水稻饲养时32日龄幼虫体重仅为茭白饲养的53.1%,而水稻种群用水稻饲养时32日龄幼虫体重为茭白饲养的79.5%。这些结果表明,茭白种群不适应取食水稻,而水稻种群对取食茭白则有一定的适应能力。根据这些结果,我们认为：（1）这两个种群已出现种下分化的迹象;（2）茭白种植不会对水稻田二化螟的发生产生大的影响。     

Ecdysteroids and adult diapause in the Colorado potato beetle, Leptinotarsa decemlineata

ABSTRACT. The difference in ecdysteroid activity in short-day (10-h photo-phase) and long-day (16-h photophase) Leptinotarsa decemlineata Say adults was characterized by high performance liquid chromatography, which revealed that for short-day beetles ecdysterone and ecdysone are the major constituents of the free ecdysteroids, whereas in long-day beetles products co-migrating with 2-deoxyecdysone and 2-deoxyecdysterone are just as abundant. Ecdysteroids were detected (15 ng/ml) only in the haemolymph of females. Ligation experiments showed that the induction of the diapause syndrome by inactivation of the corpora allata or the brain not only resulted in the formation of the typical diapause proteins but also in an increase of the ecdysteroid activity. It is suggested that adult diapause in L.decemlineata is regulated by a multifactorial system.     

稻田三种捕食性天敌与两种害虫共存系统捕食量的研究

有关捕食者-猎物关系的研究一直是种群生态学的活跃课题。Lotka-Volterra(1925)方程是最早用于研究捕食者-猎物系统的数学模型。此后许多作者进一步研究了捕食者-猎物(寄主-寄生物)的关系(Nicholson和Bailey,1935;Holling,1959;Hassell和Varley,1989;Murdoch,1969;Manley等,1972;李超等,1982,1983;丁岩钦等,1983;兰仲雄     

Geographic variation of reproductive diapause in the Drosophila auraria complex (Diptera: Drosophilidae)

ABSTRACT. In the Drosophila auraria complex (D. auraria Peng, D. biauraria Bock & Wheeler, D. triauraria Bock & Wheeler, D. quadraria Bock & Wheeler and D. subauraria Kimura), D. triauraria from the island of Yaku (30.3N in latitude) and D. quadraria from Taiwan (24.1N) had no or weak diapause, while strains of all the four species from the main islands of Japan had a firm reproductive diapause. These strains entered diapause at short daylengths and the critical daylength was longer and the incidence of diapause higher at a low rather than high temperature. In each species, the critical daylength was longer in strains from higher latitudes. Among sympatric populations of different species, D. subauraria always had the longest critical daylength, while D. auraria had the shortest one. The populations of D. biauraria and D. triauraria had longer critical daylengths than the sympatric populations of D. auraria , but this difference became smaller northwards. Since a longer critical daylength induces diapause earlier in autumn, D. subauraria would enter diapause earliest among these species, and D. auraria would do so latest. The late start of diapause in D. auraria may be related to its adaptation to domestic environments. On the other hand, the adaptive significance of the late start of diapause in northern populations of D. biauraria and D. triauraria is not clear.