Life Cycle and Mating Behavior of Belonolaimus longicaudatus in Gnotobiotic Culture

The life cycle of Belonolaimus longicaudatus was observed in vitro on excised roots of Zea mays. Roots were cultured on Gamborg''s B5 medium in petri dishes with 1.5% agar adjusted to pH 5.8 and incubated at 28 °C in darkness. Second-stage juveniles (J2) fed on the roots and started the second molt (M2) to the third-stage juveniles 2 days after inoculation (DAI). The third molt (M3) to the fourth-stage juveniles occurred 7 DAI, followed by the fourth molt (M4) to males 13 DAI or to females 14 DAI. Nematode gender differences were observed by the end of the fourth molt. The first male appeared 15 DAI and the first female 17 DAI, after which mating occurred. Males were attracted to females, and mating was observed. Mating was required for reproduction. Fertilized females began to lay eggs 19 DAI and continued egg laying without the further presence of males during a 90-day observation. All of the eggs hatched. Unfertilized females rarely laid eggs, and none of the eggs were able to hatch. Feeding took place between each molt and before egg deposition occurred. The first-stage juveniles molted in the eggs 4 days after deposition, and J2 hatched from eggs 5 days after egg deposition. The life cycle from J2 to J2 was completed in 24 days.     

Phenotypic quality and molt in the barn swallow, Hirundo rustica

Phenotypic quality may determine the development and expressionof secondary sexual characters. We studied the relationshipbetween molt and several measures of phenotypic quality in thesexually size-dimorphic barn swallow (Hirundo rustica) in itswinter quarters in Namibia. Males were in a more advanced stageof molt than females and juveniles, and the speed of molt asdetermined from the residual of the regression of the size ofthe gap in wings caused by missing and growing feathers on wingmolt score (residual wing raggedness) was also higher in malesthan in females and juveniles. Male barn swallows with longand symmetric tail feathers had a more advanced stage of moltand molted at a higher speed than males with short and asymmetrictails. Long-tailed females had a delayed molt, and females withasymmetric tails had less advanced molt and lower rates of feathergrowth than females with symmetric tails. Molt of secondariesin juveniles also appeared to be less advanced if they had longtails. Adult barn swallows molted their tail feathers in anirregular sequence with the longest, outermost tail featherusually replaced before the second or the third outermost feathers.Good body condition was positively associated with a high moltscore for some feather tracts and a rapid wing molt in adultfemales and tail molt in juveniles. Mallophaga were only weaklynegatively associated with primary and secondary molt scorein adult females and speed of wing molt in adult males. In conclusion,phenotypic quality of adult male barn swallows as reflectedby the expression of their secondary sexual character duringthe previous molt reliably reflected stage and speed of currentmolt.     

In vitro Cultivation of the Entomogenous Nematode Filipjevimermis leipsandra

The mermithid nematode, Filipjevimermis leipsandra, was successfully cultivated to the preadult stage in Schneider''s Drosophila medium supplemented with 20% fetal bovine serum. Upon transfer to a solid substrate the preadults continued to develop into ovipositing adult females. Four molts were observed. The first molt occurred in the egg. The second occurred after 6-8 days in culture during which the very thin cuticle was shed completely. The third molt occurred after 18-20 days in culture; the cuticle was retained by the third-stage nematode. This stage was considered comparable to the preadult stage that emerges from host larva, Diabrotica spp. The fourth molt occurred within 12 days after the preadult was transferred from the liquid medium to a solid substrate. Adult females began ovipositing viable eggs 1-3 days after the final molt.     

Life Cycle of Steinernema scapterisci Nguyen &Smart, 1990

The life cycle of Steinernema scapterisci Nguyen and Smart, 1990 consists of an egg stage, four juvenile stages, and an adult stage (male and female). The cycle from IJ (third stage infective juveniles) to IJ may proceed by one of two routes. If the nutrient supply is sufficient and the population is not overcrowded, the IJ develop to adult males and females of the first generation. Most eggs from these adult females hatch and the juveniles develop through each life stage to become adult males and females of the second generation. Eggs produced by these females develop to IJ. This cycle takes 8-10 days (long cycle) at 24 C. If the nutrient supply is insufficient or if overcrowded, the IJ develop to adult males and females of the first generation, and eggs produced by the females develop directly to IJ. This cycle takes 6-7 days (short cycle). The nematode is less tolerant of lower temperatures and more tolerant of higher temperatures than are other species of the genus. The sex ratio is influenced by temperature. At 15 and 24 C, females constituted 54% and 60% of the population, respectively, but at 30 C females constituted 47% of the population.     

Late breeding season definitive prebasic molt in males,and late breeding season brood care by females,in central California Wilson’s warblers

I made observations of a central California population of Wilson''s Warbler, Cardellina pusilla, after July 1 over 10 breeding seasons. I sighted males in definitive prebasic molt from July 4 (in 2007) to September 1 (in 1999). Most territorial males molted on their breeding territories, and individual molt lasted up to 46 days. Following prebasic molt, territorial males engaged in subdued “post‐molt singing,” which lasted about 7 days in some males, and which I first heard on August 13 (in 2004) and last heard on September 6 (in 1999). I sighted no female in definitive prebasic molt, or in fresh basic plumage, during the study. Of 13 females sighted ≥ July 21, 11 were in late breeding season uniparental brood care, and I could not rule out late brood care for the other two. Most, and possibly all, females not engaged in late season uniparental brood care apparently vacated their breeding territories before July 21. This departure was much earlier than for resident males, the last of which I sighted on September 10 (in 1999). Early‐departing females presumably underwent prebasic molt after July 21 at locations not known. Remaining late‐nesting females must have molted much later than resident males and likely later than early‐departing females, and at locations unknown. I last sighted two uniparental brood‐tending females, still in worn plumage, on August 26 and 29, respectively. Two unique findings of this study are a male/female difference in location of prebasic molt, and a likely dichotomy of prebasic molt timing between females leaving their breeding territories early and those remaining in uniparental brood care. Another finding, post‐molt singing in most and possible all territorial males, is a largely unrecognized behavior, but one previously reported in several passerine species. Post‐molt singing may reliably indicate completion of prebasic molt.     

Sensitive periods for wing development and precocious metamorphosis after precocene treatment of the brown planthopper,Nilaparvata lugens

The critical periods for juvenile hormone suppression of wing development and metamorphosis were examined in a pure brachypterous line of Nilaparvata lugens following topical application of Precocene II (PII) to various stages of the third and fourth nymphal stadia. When PII, in doses ranging from 10 pg to 100 ng, was applied to 12-h-old third or 6-h-old fourth stadium nymphs, long-wing formation (macroptery) was induced. Macropter induction ranged from 5 to 50% in females and from 30 to 50% in males, the effect being more prominent in males. The sensitive period for macropter induction lasted from the early second stadium through to day one of the fourth (penultimate) stadium. Beyond that period nymphs required sensitivity to PII and the numbers of macropters increased towards the final nymphal molt, again males were more sensitive. On the other hand, periods sensitive to PII for precocious metamorphosis induction appeared from early second stadium to 18 h after molting to the third nymphal stadium. Overlapping application of JH-III with PII at early third stadium could totally inhibit the occurrence of precocious metamorphosis and significantly rescue the macropter induction. From the data described, a scheme is presented for the control of wing development and metamorphosis by juvenile hormone, assuming two types of threshold value determining wing form and metamorphosis.     

Life cycle and mating behavior of <Emphasis Type="Italic">Helicotylenchus multicinctus</Emphasis> (Nematoda: Hoplolaimidae) on excised <Emphasis Type="Italic">Musa cavendishii</Emphasis> roots

The life cycle and mating behavior of Helicotylenchus multicinctus (Nematoda: Hoplolaimidae) were observed in vitro on excised roots of Musa cavendishii in gnotobiotic culture. Eggs hatched into juveniles whose appearance and structure were similar to those of the adults. Juveniles grew in size and each juvenile stage was terminated by a molt. H. multicinctus had four juvenile stages. The first molt occurred outside the egg shortly after hatching. After the final molt the juveniles differentiated into adult males and females. Mating was required for reproduction. After mating, fertilized females began to lay eggs. The life cycle from second stage juvenile to second stage juvenile was completed in 39 days.     

Trichinella spiralis: Morphological characteristics of male and female intestine-infecting larvae

The sex of encysted and excysted intestine-infecting T. spiralis larvae can be distinguished by the following morphological characteristics: the male larva has a long (approx 50 μm) rectum, and the anterior part of the testis is curved posteriorly. The female larva has a shorter rectum (approx 25 μm), a telogonic ovary, coiled uterine and seminal receptacle primordia, and a vaginal primordium. In paraffin sections males can be recognized by the spermatocytes which are of the same size. The oocytes vary in size: the smallest are located in the ventral portion, the largest on the dorsal portion of the ovary. Sex of the larvae can be differentiated by the length of the rectum as early as the tenth day, by the curvature of the anterior part of the testis and by the uterine primordium by the eleventh day, and by the presence of the vaginal primordium by the thirteenth day of intramuscular development. Farre's Organ is believed to be the primordium of the seminal receptacle.     

Variation among Populations of Belonolaimus longicaudatus

Three North Carolina populations of Belonolairnus longicaudatus differed significantly from three Georgia populations in stylet measurements, the c ratio, the distance of the excretory pore from the anterior end for both sexes; the a ratio for females only; and the total body length, tail length, and spicule length for males only. The Georgia nematodes were stouter, and the females possessed sclerotized vaginal pieces. The distal portion of the spicules of North Carolina males had an indentation and hump lacking in those of the Georgia males. The haploid number of chromosomes was eight for males from all populations of B. longicaudatus and a North Carolina population of B. maritimus. Interpopulation matings of the Tarboro, N.C. and Tifton, Ga. populations indicated that the offspring produced were infertile. Morphological differences and reproductive isolation suggest that the North Carolina and the Georgia populations belong to different species.     

Postembryonic Development of the Redwood Nematode,Rhizonema sequoiae (Nemata: Heteroderidae)

Second-stage larvae of Rhizonema sequoiae Cid del Prado Vera et al. developed into adult females in 6 months or adult males in 3 - 4 months on roots of Sequoia sempervirens maintained in a growth chamber at 16 C with a 12-hour light period. Under these conditions the second-stage larvae increased in diameter, the central cells of the genital primordium increased in size, and their nuclei enlarged. Mesenchymal cells accumulated in the esophageal and tail regions. Second-stage larvae become third-stage males or females 2 months after inoculation of redwood roots. Their sex could be distinguished by the ratio of length to width of the genital primordium, 3.4 for males and 1.6 for females. The stylet in both sexes became slender, the median bulb became robust and almost spherical, and rings of punctation on the cuticle were evident. Fourth-stage females developed in 3 months from the time of inoculation, and fourth-stage males in slightly less time. At this stage the females were more swollen than the males, the rectum was conspicuous, their reproductive system was in the process of elongation, and the annulation of the cuticle was more evident. The ratio of males to females was 2.3. Mature females were completely inside the roots and did not form cysts. The cuticle was entirely annulated, and the first eggs were detected inside the female 4 months after inoculation and started the production of abundant gelatin-like material. The new generation of second-stage larvae hatched inside the female 2 months after she matured, completing the life cycle in 8 months. The redwood nematode also completed its life cycle in 8 months under greenhouse conditions, but the ratio of males to females increased to 7.4. The entire nematode population died out at 25 C after 6 months. In a Marin County, California, forest, where this nematode occurs naturally, the temperature averaged only 9 C over the November to June period of this study, and the redwood nematode reached the fourth stage with a male-to-female ratio of 1.8.     

Phocanema decipiens: Molting in seals

Infective larvae of the anisakine nematode Phocanema decipiens from the muscle of Atlantic cod (Gadus morhua) were fed to harbor seals (Phoca vitulina) and gray seals (Halichoerus grypus). During maturation in the stomach of seal hosts, P. decipiens molted twice; these molts are the third and fourth of its life cycle. The third molt occurred between the second and fifth days of infection. The third stage, i.e., infective larva entering the third molt, had a cuticular tooth ventral to the mouth; the fourth stage larva emerging from the third molt had three bilobed lips with dentigerous ridges. The fourth molt occurred between the 5th and 15th days in seals. A female nematode emerging from the fourth molt possesses a vulva and a vagina; a male possesses caudal alae, pre- and postanal papillae. Significant morphometric changes in nematodes were associated with both molts. Females and males of P. decipiens reached maturity after 15 to 25 days in seals. Ova were detected in the feces of the seal hosts as early as the 16th day.     

Karyotypic conservatism in samples of Characidium cf. zebra (Teleostei, Characiformes, Crenuchidae): Physical mapping of ribosomal genes and natural triploidy

Basic and molecular cytogenetic analyses were performed in specimens of Characidium cf. zebra from five collection sites located throughout the Tietê, Paranapanema and Paraguay river basins. The diploid number in specimens from all samples was 2n = 50 with a karyotype composed of 32 metacentric and 18 submetacentric chromosomes in both males and females. Constitutive heterochromatin was present at the centromeric regions of all chromosomes and pair 23, had additional interstitial heterochromatic blocks on its long arms. The nucleolar organizer regions (NORs) were located on the long arms of pair 23, while the 5S rDNA sites were detected in different chromosomes among the studied samples. One specimen from the Alambari river was a natural triploid and had two extra chromosomes, resulting in 2n = 77. The remarkable karyotypic similarity among the specimens of C. cf. zebra suggests a close evolutionary relationship. On the other hand, the distinct patterns of 5S rDNA distribution may be the result of gene flow constraints during their evolutionary history.     

Juvenile hormone-dependent vitellogenin synthesis in Locusta migratoria fat body: Inducibility related to sex and stage

Juvenile hormone (JH)-dependent vitellogenin (Vg) synthesis in the fat body of Locusta migratoria is normally limited to sexually mature adult females. As a step toward examining the basis of this limitation, we have tested female and male locusts in a series of stages after the third larval molt for inducibility of Vg synthesis by the synthetic JH analog, methoprene. We find that in the fourth and fifth larval instars fat body of both sexes can be induced to produce Vg, but in the adult stage females respond strongly while no more than trace amounts can be induced in males. Quantitative assays show relative responsiveness in the order: adult female > fifth instar female > fifth instar male ? adult male. During the fifth instar of both sexes, maximal vitellogenic response was obtained in midinstar. After the larval-adult ecdysis, female fat body was unresponsive during the first 4 days, then responsiveness increased and by Day 8 after ecdysis fat bodies were fully as competent to produce Vg as at Day 14, the usual maximum of the first vitellogenic cycle due to endogenous JH. Larval and adult female fat bodies implanted into male larvae are competent for Vg synthesis after metamorphosis, so that the differences between adult male and female cannot be imposed by the male milieu intérieur during the larval-adult molt. In male and female precocious adults, produced by treatment of fourth instars with precocene, fat body responded to methoprene as in normal adults. We conclude that factors intrinsic to the fat body cells, determined early in development, are responsible for differential gene programing in males and females, which is partially expressed by the fifth instar but fully manifest only after a molt in the absence of JH.     

Overwintering Stages of Meloidogyne incognita in Vitis vinifera

The overwintering of Meloidogyne incognita in and around Vitis vinifera cv. French Colombard roots was studied in a naturally infested vineyard at the Kearney Agricultural Center, in a growth chamber, in inoculated vines in microplots at the University of California, Davis, and in a greenhouse. Infected roots were sampled at intervals from onset of vine dormancy until plants accumulated about 800 degree days (DD - base 10 C). Embryogenesis within eggs, classified as less than or more than 16 cells and fully differentiated, and numbers of juveniles (second to fourth stage) and preovipositional and mature (egg-laying) adult stages in roots were determined. All stages were present at the onset of dormancy. Juveniles and immature females were not recovered during the dormant period. Mature females and eggs were always present in roots, although the number of mature females generally decreased with time after onset of dormancy. In contrast, in a greenhouse experiment that accumulated comparable DD without the host plant going through dormancy, the number of mature females increased. After bud break, the number of eggs per female increased and all nematode stages were found in host roots. Eggs in all stages of embryogenesis were observed at all times of sampling, indicating that females overwinter and are capable of laying eggs when conditions improve in the spring and need to be considered in nematode management decisions.     

An outbreak of Caparinia tripilis in a colony of African pygmy hedgehogs (Atelerix albiventris) from Korea

In February 2010, dermatitis characterized by scale and self-trauma due to puritis was recognized in a group of 22 four-toed hedgehogs (Atelerix albiventris Wagner, 1841) from a local pet shop in Gwangju, Korea. Microscopic examinations of skin scraping samples showed numerous mites of all developmental stages. Morphologically, pedicels of adult mites were short and unjointed. Tarsal caruncles were bell-shaped on all legs of males while they were absent on legs III and IV of females. Three long setae on the third pair of legs in both sexes were present. Adult males had posterior end of the abdomen with trilobate projection on each side, each lobe with a long seta. Based on these features, the mites were identified as Caparinia tripilis. This is the first report of caparinic mite infestation in hedgehogs from Korea. Identification keys for the family Psoroptidae and the genus Caparinia are provided.     

Heterodera raskii n. sp. (Heteroderidae: Tylenchina), a Cyst Nematode on Grass, from Hyderabad,India

Heterodera raskii n. sp. is described and illustrated from specimens collected from roots of bulb grass, Cyperus bulbosus, in Hyderabad, India. The new species belongs to the ''goettingiana'' group and differs from closely related H. cyperi by the elongate ovoid shaped cysts and females, greater fenestral length, width, vulval slit, and absence of egg sac. The stylet knob shape was round in second-stage juveniles and posteriorly sloping in females and males of H. raskii n. sp., while it was anteriorly directed in second-stage juveniles and spherical in females and males of H. cyperi.     

Mating of captive thirteen-lined ground squirrels and the annual timing of estrus

Thirteen-lined ground squirrels (Spermophilus tridecemlineatus) have a single annual mating season in Michigan, beginning shortly after their spring emergence from hibernation. Captive females were studied during a 3-year period to determine relations among time of removal from the coldroom, vaginal estrus, and mating behavior. Following a 7-month period females spent in a coldroom, vaginal lavages were taken daily to monitor changes in estrous condition. Females removed from the coldroom about when free-living animals emerge from hibernation were in vaginal estrus within 24-48 hr and had an initial period of persistent estrus (ca. 3 weeks), followed by briefer (less than 1 week) and more sporadic estrous periods. Females left in the coldroom 3 weeks longer than normal had significantly briefer initial periods of vaginal estrus after being removed from the coldroom. Similarly, virgin Yearlings and virgin 2-Year-Olds had significantly briefer initial periods of estrus than nonvirgin Adults (greater than or equal to 2 years old). In 1985, eight of eight females paired with males mated within the first week after removal from the coldroom and subsequently produced litters. Mated females remained in vaginal diestrus from within a few days of mating until after parturition. In contrast, unmated females remained in prolonged vaginal estrus during this period. Females first paired with males 3 weeks after being taken from the coldroom failed to mate. In 1986, five of six females first paired with males 2 weeks after being removed from the coldroom similarly failed to mate. However, five of six females did mate that were removed from the coldroom 10 days after those in the previously described group and paired with a male 4 days after removal. This first report of reliable mating behavior in captive thirteen-lined ground squirrels should facilitate subsequent analysis of reproductive patterns in this species.     

First descriptions of copepodid stages, sexual dimorphism and intraspecific variability of Mesocletodes Sars, 1909 (Copepoda, Harpacticoida, Argestidae), including the description of a new species with broad abyssal distribution

Mesocletodes Sars, 1909a encompasses 37 species to date. Initial evidence on intraspecific variability and sexual dimorphism has been verified for 77 specimens of Mesocletodes elmari sp. n. from various deep-sea regions, and ontogenetic development has been traced for the first time. Apomorphies are a strong spinule-like pinna on the mx seta that is fused to the basis, P2-P4 exp3 proximal outer seta lost, P1-P4 enp2 extremely elongated, furcal rami elongated, female body of prickly appearance, female P2-P4 enp2 proximal inner seta lost. Intraspecific variability involves spinulation, ornamentation and size of the body and setation and spinulation of pereiopods. Sexually dimorphic modifications of adult females include prickly appearance of the body, P1 enp exceeds exp in length, P1 coxa externally broadened, seta of basis arising from prominent protrusion, hyaline frills of body somites ornate. Sexual dimorphism in adult males is expressed in smaller body size, haplocer A1, 2 inner setae on P2-P4 enp2 and on P5 exp, P5 basendopodal lobe with 2 setae. Some modifications allow sexing of copepodid stages. The female A1 is fully developed in CV, the male A1 undergoes extensive modifications at the last molt. P1-P4 are fully developed in CV. Mesocletodes faroerensis and Mesocletodes thielei lack apomorphies of Mesocletodes and are excluded.     

Description and Larval Heteromorphism of Hoplolaimus concaudajuvencus,n. sp. (Nematoda: Hoplolain-lidae)

Hoplolaimus concaudajuvencus n. sp., of the genus Hoplolaimus Daday, 1905, characterized by larval heteromorphism, is described and illustrated as recovered from ryegrass/bermudagrass golf green turf in Florida. Females and males are closely related to H. galeatus (Cobb, 1913) Thorne, 1935, but have longer stylets with more definitely tulip-shaped stylet knobs which anteriorly tend to close upon the stylet shaft more than in H. galeatus. First and second-stage larvae have a conically-pointed tail unlike any known species of the genus. Subsequent stages, including females, have rounded tails essentially similar to other species of the genus and males possess the typical hopolaimid tail and bursa. The first molt was found to occur within the egg.