Long-term changes in the oviposition behaviour of the cabbage butterfly, Pieris rapae, induced by contact with plants

ABSTRACT. Contact between the tarsi and cabbage foliage was found to have important influences on the oviposition behaviour of Pieris rapae , whereas contact between the ovipositor tip and cabbage foliage showed no influence. Oviposition on a leaf disc was not influenced by the presence of previously laid eggs. Gravid female P.rapae showed an increased tendency to approach and land on host or non-host foliage, or on yellow or green cards, after tarsal contact with cabbage foliage. This effect persisted for at least 72h. It was accompanied by an increased tendency to oviposit on non-host plants, most obviously within seconds of contact with cabbage, but with some persistence after 72h. Contact with a non-host leaf (lettuce) reduced the tendency of females to land on plants, but this effect was less pronounced than the one induced by contact with cabbage. These behavioural changes were immediate as well as long-term and were not associated with changes in the ovaries, so they probably result from the direct effects of sensory input on the CNS. Such behaviour probably increased the likelihood that gravid females would locate host-plants for oviposition in the field. For tests of host-plant specificity, the implications are that the behaviour of gravid females towards an array of plants might differ according to the presence or absence of hosts, not only during the test, but also during the preceding several days.     

Acoustic communication in an electric fish,Pollimyrus isidori (Mormyridae)

It has been known since von Frisch's work in the 1930's that mormyrid electric fishes are quite sensitive to sound. We now describe a repertoire of natural sounds produced by the mormyrid, Pollimyrus isidori, during breeding and aggression; reception of communication sounds is probably a major function for mormyrid audition. In aquaria, Pollimyrus isidori produce 'grunts', 'moans', 'growls', 'pops' and 'hoots' at various phases during nesting, courtship, and territory defense. All five sounds are produced primarily at night. Territorial males produce grunts, moans and growls during courtship. Vocalizing is stimulated by the presence of a gravid female on the male's territory and decreases with the onset of spawning. Hoots and pops are given during agonistic behavior. Grunts are bursts of acoustic pulses, stereotyped for an individual, with the potential as individual signatures. The electric organ is silent during grunts and moans and is discharged at a reduced rate during growls. The courtship and spawning of Pollimyrus isidori is described.     

Locomotor impairment of gravid lizards: is the burden physical or physiological?

Pregnancy is associated with reduced locomotor performance in several reptile species, but the reasons for this reduction remain unclear. Previous authors generally have assumed that the decreased maternal mobility is due to the physical burden of the clutch, but our data on a viviparous Tasmanian scincid lizard (Niveoscincus microlepidotum) suggest a different interpretation. Running speeds of gravid female skinks decrease during gestation (as litter mass increases), but this locomotor impairment is due to physiological changes associated with pregnancy, rather than simple physical burdening. Maternal running speeds are unrelated to litter masses, and do not increase in the week after parturition. Females with very large abdominal fat‐bodies (due to ad libitum feeding in the laboratory), equivalent in mass to the litter, nonetheless run rapidly. If the locomotor ‘costs’ of reproduction reflect all‐or‐none physiological changes associated with pregnancy, then the magnitude of such costs may correlate only weakly with the actual level of reproductive investment. Because life‐history models predict that the relationship between fecundity and ‘cost’ has important evolutionary consequences, our results highlight the need to clarify the causal basis for locomotor impairment in gravid reptiles.     

Decreased reproductive rate of the spider,Nephila clavata,inhabiting small woodlands in urban areas

The reproductive characteristics and feeding conditions of the spider,Nephila clavata, were examined at some urban and non-urban woodland sites. More than 80% of females were gravid by late October in both non-urban and large urban woodlands, whereas only 10%–30% were gravid in small urban woodlands. The expected number of eggs per female in mid-October was also lower in the small urban woodlands, although body length was not reduced. This suggests that reproductive failure was not caused by food shortage during the nymphal stage. Relative food consumption rate, prey size, biomass and size of potential prey during the adult stage all tended to be lower in small urban woodlands. These results suggest that decreased reproduction ofN. clavata in small urban woodlands is caused by food shortage during the adult stage, particularly a shortage of large insects.     

Belly up: Reduced crevice accessibility as a cost of reproduction caused by increased girth in a rock‐using lizard

Costs of reproduction are any aspect of current reproduction that has the potential to reduce survivorship or reproductive output, and may include physiological costs or increased risks. Females of many species experience increased body mass, and increased girth, when gravid. Increased body mass reduces running speed and increases the cost of locomotion during pregnancy, but few studies have examined the cost of increased girth. If increased girth of gravid females reduces access to shelter from predators or the elements, increased girth could constitute a cost of reproduction. In the laboratory, we experimentally tested whether access to crevices was limited in viviparous, saxicolous female lizards (Eulamprus brachysoma), which use crevices for shelter, by measuring access to artificial crevices of known widths, and body height during and after pregnancy. Gravid E. brachysoma had significantly greater body height (11.2% on average), and as a result were forced to use significantly wider crevices (18.4% wider on average) than post‐parturition. Females with larger clutch sizes had wider mid‐bodies and required larger crevices. Control females, which were not gravid at either time of testing, showed no significant change in the size of crevice they could enter over time. If access to narrow crevices provides advantages such as protection from predators, or is important for thermoregulation, then gravid females may suffer a cost of reproduction because their access to narrower crevices is limited.     

Characteristics and analysis of uterine electromyographic activity in pregnant cows

The electromyographic activity of the cow uterus in the last trimester of pregnancy was investigated. The investigation was performed on 12 animals and the electrical activity was recorded in the last trimester of pregnancy during 11 different periods until the delivery. The duration of the action potential bursts (APB) recorded during the first 7 periods, was small. It did not exceed 2 seconds. A significant increase, however, was recorded at 7 to 9 days before the labor and it involved all the investigated areas in the uterus. The number of APB of the gravid horn was significantly higher than that recorded at other locations in the uterus with the exception of the day of delivery. A significant correlation was found between the number of APB and the level of magnesium in blood serum. The levels of 17-beta estradiol and progesterone were similar during all studied periods with the exception of the last week, in which a dramatic fall in estradiol level and a significant increase in the progesterone concentration were observed. The results showed that it is possible to distinguish three different phases of electric activity in the cow uterus during the last trimester of pregnancy. The features of these phases were discussed.     

Pattern of electrical activity of the ovine uterus and cervix from mating to parturition

The electrical activity of the uterus, greater curvature and lesser curvature, and of the cervix were recorded throughout several oestrous cycles, matings and the entire course of pregnancy in a set of ewes. In cyclic ewes, all electrode sites were active during the periovulatory period, but during the luteal phase only the cervix and lesser curvature continued to present regular activity, i.e. episodes of 6-8 min duration. Matings failed to disrupt the oestrous activity pattern in 5 out of 6 ewes. During the subsequent pregnancy in 4 ewes, activity, when present, consisted of the cyclic occurrence of regular activity episodes in the gravid horn(s) (greater curvature) and in the cervix (and lesser curvature in 1 ewe). Three phases were recognized on the basis of the activity of the greater curvature of the gravid horn(s). The first phase corresponded to quiescence of the horn from Day 5 (Day 0 = mating) to about Day 41. The second phase was marked by the sudden onset of regular activity of the uterus; frequency rapidly increased and maximal values were reached around Day 49, after which frequency progressively decreased until around Day 66. The third phase was characterized by a steady state in genital tract activity until the peripartum period. The cervix and lesser curvature activity followed an almost similar development of regular activity episodes with only slight time differences.     

Reproductive stage and history affect the phonotactic preferences of female midwife toads, Alytes muletensis

We investigated whether the reproductive stage or reproductive history of females affects their preferences for male calls that differ in frequency. We repeatedly tested gravid female midwife toads prior to and immediately after mating, and during ovulation. When females were ovulating they were much more consistent in their choice of call than when they were gravid but not ovulating. When females had recently mated they still showed positive phonotaxis, but did not reliably discriminate between alternative calls. This study is the first to test gravid female anurans repeatedly at different stages in their reproductive cycle (ovulating or not; pre- and postmating). It highlights the need to treat with caution the results from population-based preference studies in which individuals are tested only once, and in which variation in reproductive state is not taken into account. Copyright 2000 The Association for the Study of Animal Behaviour.     

Blood-feeding of Tunga penetrans males

The jigger Tunga penetrans (Linnaeus, 1758: type-species of the family Tungidae) is the smallest known species of flea (Siphonaptera), causing serious ectoparasitosis of humans and domestic animals. The adult female Tunga lodges in the epidermis of the mammalian host, grows by neosomy, becomes gravid and expels eggs. Relatively little is known about the free-living male Tunga adults. Among impoverished communities of Fortaleza in north-east Brazil, we observed T. penetrans males as well as females penetrating the skin of human hosts. After penetrating the epidermis for a few hours, evidently for capillary feeding from the dermis, males withdrew their mouthparts and crawled away, whereas the females remained completely embedded, hypertrophying to become gravid, eventually dying in situ after oviposition. Caged rats were placed on the sandy soil and examined periodically for Tunga infestation. On five rats we obtained 140 females embedded and we detected 75 males biting, with rat erythrocytes observed in the proventriculus and midgut of all five males dissected and examined microscopically. This confirms that T. penetrans males are hamatophagous ectoparasites of mammals.     

Costs of anorexia during pregnancy in a viviparous snake (Vipera aspis)

Spontaneous anorexia has been documented in various animal species and is usually associated with activities competing with food intake. In natural conditions, most female aspic vipers (Vipera aspis) stop feeding during the two months of pregnancy. We carried out a simple experiment on 40 pregnant females to determine whether anorexia was obligatory or facultative, and to investigate the energetic consequence of fasting on post-partum body condition and litter traits. Three diet treatments were applied during gestation: no food, one feeding occasion, and two feeding occasions. Twelve nonpregnant, unfed females were used as a control group. Most gravid females accepted captive mice during gestation, suggesting that anorexia reported in the field was a side effect of the tremendous changes in activity pattern associated with pregnancy. Mass loss was high for unfed reproductive females, indicating high energy expenditure associated with embryo maintenance. Prey consumption allowed compensation for metabolic expenditure and enhanced post-partum female body condition, but had no effects on litter characteristics. The magnitude of the metabolic expenditure during gestation appeared to be independent of fecundity.     

Pregnancy rates and gravid uterine parameters in single, twin and triplet pregnancies in naturally bred ewes and ewes after transfer of in vitro produced embryos

The objectives of this study were to: (1) evaluate the pregnancy rates after transfer of embryos produced in the presence or absence of epidermal growth factor (EGF) during in vitro maturation, and (2) compare several variables of the gravid uterus on day 140 after fertilization in single, twin and triplet pregnancies in ewes (n = 12) bred naturally and in ewes (n = 18) after transfer of embryos produced in vitro. Oocytes collected from FSH-treated ewes (n = 18) were collected from all visible follicles and cultured in maturation medium with or without EGF. Oocytes were then fertilized in vitro by frozen-thawed semen. On day 5 after fertilization, embryos with > or = 16 cells were transferred to recipient ewes (n = 39). In addition 12 ewes were bred naturally. Pregnancy was verified by real-time ultrasonography on day 45 or later after embryo transfer (ET) or breeding. On day 140 of pregnancy, the reproductive tract was collected from all ewes and the following parameters were determined: the number, sex, weight and crown to rump length (CRL) of fetuses, weights of gravid uterus and fetal membranes, and weight and number of placentomes. Presence of EGF in maturation medium increased (P < 0.04) cleavage rates (78% versus 59%) and percentage of > or = 16 cell embryos on day 5 after fertilization (62% versus 40%). Pregnancy rates tended to be greater (P < 0.1) after transfer of embryos matured in the presence of EGF (52%) than in the absence of EGF (39%). EGF presence in maturation medium did not affect any variables of gravid uterus or fetal weight. For single pregnancies in naturally bred ewes and ewes after ET all uterine variables were similar. For twin pregnancies, weight of gravid uterus, weight of uterus plus fetal membranes, total weight of placentomes/ewe, mean weight of individual placentome, mean weight of fetus, total fetal weight/ewe and CRL were greater (P < 0.0001-0.04) for ewes after ET than for ewes bred naturally. The weights of gravid uterus, fluid, uterus plus fetal membranes, fetal membranes, total placentomes/ewe, mean weight of individual placentome and total fetal weight/ewe were greater (P < 0.0001-0.08) for triplet pregnancies in ewes after ET than single and twin pregnancies in ewes naturally bred or after ET. The number of placentomes/fetus was greatest (P < 0.0001-0.06) in single pregnancies in ewes bred naturally and after ET fewer in twin pregnancies in ewes bred naturally and after ET and fewest in triplet pregnancies in ewes after ET. The total number of placentomes/ewe was greatest (P < 0.0001-0.06) for twin pregnancies in ewes naturally bred, fewer in single pregnancies in ewes naturally bred and twin and triplet pregnancies after ET, and fewest in single pregnancies in ewes after ET. The mean weight of fetus was greater (P < 0.0001-0.07) in single pregnancies in ewes naturally bred or after ET than in twin or triplet pregnancies in ewes naturally bred or after ET. The CRL was the lowest (P < 0.01) in twin pregnancies in ewes bred naturally. For pregnancies after natural breeding and after ET, the number of fetuses/ewe was negatively correlated (P < 0.03-0.0001) with the weight of placentomes/fetus, the number of placentomes/fetus, the mean weight of the fetus and CRL, and was positively correlated (P < 0.0001-0.05) with weight of gravid uterus, the total number of placentomes/ewe and total fetal weight/ewe. These data demonstrate that the presence of EGF in maturation medium increases the rates of cleavage and early embryonic development, and has a tendency to enhance rates of pregnancy but does not affect variables of the gravid uteri in ewes after transfer of in vitro produced embryos. Transfer of embryos produced in vitro affected some uterine variables in twin but not single pregnancies to compare with pregnancies after natural breeding. In addition, culture conditions in the present experiment did not create large offspring syndrome. The low number of placentomes/fetus seen in triple pregnancies appears to be compensated for by the increase in the weight of each individual placentome.     

Distribution, behavior, and course of patency of Dracunculus insignis in experimentally infected ferrets

From 106 ferrets experimentally infected with Dracunculus insignis, 273 female worms and 42 male worms were recovered. The percentage of female worms that mated, the location of all worms, and the rate of emergence of gravid females were recorded. Of 174 mature female worms recovered, only 11% had emerged before necropsy. Eighty-one percent of the male worms and 87% of all unmated (immature) females were found on the trunk of the animal or on the skin overlying it. Gravid female worms were found on the extremities (legs) 88% of the time. Almost one-third of gravid female worms were found on the left front leg. On 4 occasions, females were found in unusual locations: the tail, the cheek, the lumbar region of the spinal cord, and the peritoneal cavity associated with the omentum. The results showed that only a small percentage of mature female worms emerge, which suggests that infected persons harbor many more gravid female worms than indicated by reports of emergent worms. More than one-third of female worms were not mated, but it is likely that these immature females would be capable of further development. Furthermore, male worms have been observed to survive for up to 330 days, suggesting that male or unmated female worms may carry over from one transmission season to the next.     

Changes in protein turnover during gestation in the foetuses,placentas, liver,muscle and whole body of rats given a low-protein diet

(1)Protein synthesis and content have been studied in skeletal muscle, liver, foetuses and placentas of pregnant rats given a protein-deficient diet. Changes which occurred during the anabolic and subsequent catabolic phases of pregnancy are compared with those in well-fed pregnant and in protein-deficient non-pregnant rats. (2) The normal increase in liver protein did not occur during pregnancy in the protein-deficient group. (3) Protein deficiency affected protein content of the placenta earlier and more severely than that of the foetus. (4) Rates of protein synthesis in liver, placentas and foetuses were enhanced above control values by protein deficiency. (5)_Muscle protein increased normally during the anabolic phase of pregnancy but fell during the catabolic phase, unlike values for weel-fed animals. (6) Muscle protein synthesis rates rose by similar amounts in well-fed and protein-deficient animals during the anabolic phase of pregnancy. The fall to starting values during the catabolic phase was sharper and earlier in protein-deficient animals, which could reduce demands on the body amino acid pool by an amount equivalent to over 50% of the needs for protein deposition in foetuses and placentas. Thus, changes in muscle protein synthesis in both anabolic and catabolic phases of pregnancy may afford some protection to foetal protein synthesis.     

Alternative reproductive tactics and courtship in the common goby

In the marine common goby Pomatoschistus microps , males either build nests and attract females to spawn or act as sneakers, forcing themselves into other males' nests during mating, to fertilize some of the eggs in the clutch. The reproductive tactics of small males were studied in the presence of surplus nest material and an excess of gravid females, while a larger, nestholding male spawned with a female. Of 24 small males, 13 only attempted to sneak, seven only courted females and/or spawned in their own nest, and four performed both behaviours. The small males who attracted females successfully were significantly larger than the ones who failed to do so. Females had been courting the small male more often when he subsequently spawned in his own nest, than when he did not get a female. The small males did not court the females very frequently, and their courtship rate did not depend on whether or not they attracted females. Instead, female courtship behaviour may be a cue for a male either to spawn as a nest holder or become a sneaker. The study pointed out the importance of female behaviour for male reproductive tactics, which could be more important in fish than is known currently.     

Reduction in locomotor ability as a cost of reproduction in gravid snakes

Summary Recent studies suggest that lower survival among gravid squamate reptiles may be partially the result of decreased locomotor ability during gestation. In this study, we compared the speed and endurance of female garter snakes (Thamnophis marcianus), before, during, and after pregnancy. Gravid snakes had significantly lower locomotor performance than did non-gravid females, and performance varied among stages of gestation, reaching a minimum 0–6 weeks prior to parturition. Both number of offspring and relative clutch mass were inversely correlated with locomotor performance; as females increased these traits, locomotor ability decreased. If reduced locomotor performance results in greater risk of predation and/or lowered foraging ability, then natural selection (operating via differential mortality or feeding rates of gravid females) may result in important constraints on both clutch size and relative clutch mass in squamates.     

Thermal biology of reproduction in viviparous skinks,Eulamprus tympanum: why do gravid females bask more?

Summary In some reptiles, gravid females bask more, and/or maintain higher body temperatures than do males or non-gravid females. This phenomenon is usually explained in terms of the female or her offspring benefitting from accelerated embryogenesis and early birth, but the effect of increased basking on gestation period has not been studied. In a laboratory experiment, gestation periods of gravid female skinks (Eulamprus tympanum) decreased with the duration of access to radiant heat. Embryonic development was more rapid in the laboratory than in the field, and there were no apparent adverse effects of this accelerated gestation on females or offspring. Number and mass of offspring, survival rates of embryos, relative clutch mass and female mass before and after parturition were not influenced by the decrease in gestation period caused by increased basking. Females selected similar temperatures in the laboratory and field (32° C), despite the availability of higher temperatures in the laboratory. Thus, gestation in the laboratory was accelerated by spending longer periods at usual basking temperatures, rather than by selecting higher temperatures. In the field, mean and modal body temperatures of active animals were similar in gravid females, males and non-gravid females, but gravid females appear to bask more of the time, even in cloudy weather when other members of the population do not bask. Hence, an apparent similarity in thermal regimes of gravid and non-gravid animals may mask significant underlying differences in thermoregulatory strategies.     

Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry as a useful tool for the rapid identification of wild flea vectors preserved in alcohol

Flea identification is a significant issue because some species are considered as important vectors of several human pathogens that have emerged or re‐emerged recently, such as Bartonella henselae (Rhizobiales: Bartonellaceae) and Rickettsia felis (Rickettsiales: Rickettsiaceae). Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) has been evaluated in recent years for the identification of multicellular organisms, including arthropods. A preliminary study corroborated the usefulness of this technique for the rapid identification of fleas, creating a preliminary database containing the spectra of five species of flea. However, longterm flea preservation in ethanol did not appear to be an adequate method of storage in the context of specimen identification by MALDI‐TOF MS profiling. The goal of the present work was to assess the performance of MALDI‐TOF MS in the identification of seven flea species [Ctenocephalides felis (Siphonaptera: Pulicidae), Ctenocephalides canis, Pulex irritans (Siphonaptera: Pulicidae), Archaeopsylla erinacei (Siphonaptera: Pulicidae), Leptopsylla taschenbergi (Siphonaptera: Ceratophyllidae), Stenoponia tripectinata (Siphonaptera: Stenoponiidae) and Nosopsyllus fasciatus (Siphonaptera: Ceratophyllidae)] collected in the field and stored in ethanol for different periods of time. The results confirmed that MALDI‐TOF MS can be used for the identification of wild fleas stored in ethanol. Furthermore, this technique was able to discriminate not only different flea genera, but also the two congeneric species C. felis and C. canis.     

Four-year study of controlled timed breeding of rhesus monkeys (Macaca mulatta)

As part of the timed breeding colony at Tulane National Primate Research Center, exogenous progesterone administration (5 mg/day for 10 days) has been used to select conception dates by inducing artificial luteal phases in female rhesus monkeys. A retrospective analysis of data obtained during four breeding seasons (1998-2001) revealed that conceptions occurred an average of 18 days after the last administration of progesterone. The age of the female to be bred, previous pregnancy history, and timing of breeding during the breeding season were determined to be critical factors in the success of the procedure. The benefit of this method of timed breeding is that it does not require tracking of menstrual cycles, which can be labor-intensive and requires that animals be monitored several months in advance of breeding to determine each female's individual cycle length. It also provided an efficient use of breeding-age males.     

Effects of gravidity on habitat use and antipredator behaviour in three-spined sticklebacks

Habitat use was examined in six Alaskan populations of three-spined sticklebacks Gasterosteus aculeatus . In three lakes with predatory fishes, gravid female sticklebacks remained closer to refuge than did non-gravid females, while those in lakes devoid of piscivores did not display this shift in behaviour. Gravid females in a lake with predatory rainbow trout Oncorhynchus mykiss used different evasive manoeuvres than did non-gravid females during in situ encounters with a model rainbow trout. Gravid females were more likely to incorporate a protean element in their flight moffements than were non-gravid females. Offerall, these data suggest that gravid female three-spined sticklebacks modify habitat use and escape behaviour to reduce vulnerability to predators.