Laboratory hybridization in green lacewings (Neuroptera: Chrysopidae: Chrysoperla): evidence for genetic incompatibility

1993 ◽  
Vol 71 (2) ◽  
pp. 233-237 ◽  
Author(s):  
Marta Martínez Wells

Courtship songs are an important reproductive barrier in lacewings of the genus Chrysoperla, so heterotypic matings should occur less readily than homotypic matings. In addition, if song morphs have become separate species, there may be some postzygotic isolation between song morphs. Two generations of crosses using sympatric P1 and P3 morphs of Chrysoperla plorabunda provide evidence for both hypotheses. In the first stage of the experiment, egg laying (an indication of mating success) was delayed by a week in heterotypic crosses compared with homotypic crosses, and hatching success of eggs from hybrid crosses was 16% lower than that from control crosses. In the second stage of the experiment, backcrosses involving P3 morph males or females were the least successful in mating. When pairs did mate, they did so a week later than in the other crosses. Thus, behavioral isolation delays heterotypic matings when females are not given a choice of mates. These results provide some genetic evidence that the song morphs of the C. plorabunda complex are biological species.

2021 ◽  
Author(s):  
◽  
Kelly Maree Hare

<p>The conditions under which reptilian eggs are incubated affect survival probability and physiological attributes of the progeny. The egg-laying skink, Oligosoma suteri, is the only endemic oviparous lizard in New Zealand. No controlled laboratory incubation had previously been undertaken, and thus no information was available on the requirements for successful captive incubation. I studied the effects of incubation regime on the eggs and hatchlings of O. suteri to four months of age. Oligosoma suteri eggs (n = 174) were randomly distributed among three constant incubation temperatures (18°C, 22°C and 26°C) and two water potentials (-120 kPa and -270 kPa). Hatching success and hatchling survival were greatest at 22°C and 26°C, with hatchlings from 18°C incubation suffering from physical abnormalities. Incubation regime and maternal influence did not affect sex of individuals, with equal sex ratios occurring from each incubation treatment. Hatchlings from the 22°C and -120 kPa incubation treatments were larger, for most measurements, and warmer incubation temperatures resulted in increased growth rates. Juveniles from 22°C and 26°C and individuals with greater mass per unit length (condition index) sprinted faster over 0.25 m. Sprint speed was positively correlated with ambient temperature. At four months of age sprint speed decreased in 18°C individuals and individuals incubated at 26°C and -270 kPa compared to their performance at one month. The results suggest that the most successful captive incubation regime for O. suteri is 22°C and -120 kPa. This study also shows that temperature-dependent sex determination does not occur in O. suteri, but that fitness traits are influenced by incubation temperature.</p>


1994 ◽  
Vol 21 (6) ◽  
pp. 621 ◽  
Author(s):  
I Williamson ◽  
CM Bull

There are few studies of embryo mortality in anurans, and most of these studies deal with anurans that deposit clutches as one egg mass. In this study, egg mortality in Crinia signifera, an anuran that distributes its clutches in small clusters of eggs, was examined with the aims of: (i) determining overall mortality levels, and (ii) determining whether there was significant variation in success between clutches laid by different females. Hatching success varied significantly between years and between habitats, and was as low as 2% in some habitats in some years. Fungal infection caused most mortality, and hatching success was higher in temporary pools than in a permanent water body. Although significant variation in clutch success between females could occur if clutches were laid in different habitats or at different times, it was not clear whether there would be significant variation in clutch success between females laying simultaneously in the same water body. Differences in success of clutches might occur if females distributed eggs at different depths or in different-sized clusters. However, information on inter-female variation in these components of egg-laying behaviour in C. signifera is currently unavailable.


The Auk ◽  
2006 ◽  
Vol 123 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Andrea A. Astié ◽  
Juan C. Reboreda

AbstractMost studies on cowbird parasitism have focused on its effects on parasitized nests, whereas few have considered the costs at nests that cowbirds visit but at which they do not lay eggs. Shiny Cowbirds (Molothrus bonariensis) peck and puncture host eggs both in nests where they lay eggs and in unparasitized nests. We analyzed the effect of egg punctures in unparasitized and parasitized nests of a large host, the Creamy-bellied Thrush (Turdus amaurochalinus; hereafter “thrush”), as well as the costs of Shiny Cowbird eggs and chicks in this host’s nests. We determined thrush egg survival, hatching success, and chick survival in successful nests, and nest survival during the egg and nestling stages. Frequency of parasitism was 60%, and its intensity 1.6 ± 0.1 eggs nest−1. Number of host eggs punctured was positively associated with intensity of parasitism. The host’s eggs were frequently punctured in parasitized nests (71%) and in unparasitized nests (42%). Egg punctures reduced the number of eggs at hatching in 23% and 49% of unparasitized and parasitized nests, respectively. Nests with egg punctures had a lower survival rate than nests without them, but nest survival was not associated with parasitism. Presence of a Shiny Cowbird egg was associated with a decrease in the hatching success of host eggs, but presence of a Shiny Cowbird chick did not have any detrimental effect on either the survival and growth rate of host chicks in successful nests or the survival of the whole nest. Our results show that egg punctures were the primary determinant of thrush reproductive success. Consequently, comparison of unparasitized and parasitized nests gives an incomplete estimation of the effects of Shiny Cowbirds on host reproductive success, because the cost of egg punctures is also important in nests where there is no Shiny Cowbird egg laying.Costos de la Perforación de Huevos y el Parasitismo por Molothrus bonariensis en Nidos de Turdus amaurochalinus


1985 ◽  
Vol 63 (3) ◽  
pp. 607-611 ◽  
Author(s):  
Ralph D. Morris ◽  
John W. Chardine

The substrate at a herring gull (Larus argentatus) colony on Lake Erie near Port Colborne, Ontario (Lighthouse), was completely covered by a thick layer of ice throughout April and early May 1982. Egg laying normally begins at this location in mid-April. An adjacent herring gull colony (Canada Furnace) was ice free. Herring gull pairs at the Lighthouse colony defended territories on top of the ice but only 3 of about 90 pairs built nests on the ice. Birds neither deserted the colony nor moved within it to ice-free areas as these became available. The mean date of egg laying at the Lighthouse colony in 1982 was about 2 weeks later than in the previous year. At the adjacent Canada Furnace colony, there was no difference in the mean date of egg laying between the 2 years. There were no differences in the distribution of clutch sizes, mean clutch sizes, or hatching success of three-egg clutches laid within ± 1 SD of the mean date of egg laying at either colony in the 2 years. By these measures, the ice-induced delay in breeding chronology of birds at the Lighthouse colony in 1982 did not adversely effect reproductive performance in that year.


2019 ◽  
Vol 9 (3) ◽  
pp. 71-73
Author(s):  
I. Ya. Truskavetska

The animal world of Ukraine is characterized by a large variety of species. Among the lepidoptera there are a lot of pests whose larvae cause significant damage to agriculture. In the paper, we investigated the seasonal and perennial dynamics of vegetable crops pests’ population of Mamestra brassicae in the agrobiocenoses of white cabbage. The basis of our study was the investigation of the relative quantity of the pest larvae, we demonstrated the damage to plants, as well as the periods of intensive emergence of the imago and the number of generations per year. In future, this will enable the development of effective ecologically sound methods for controlling the number of species of white cabbage pests in the conditions of Kamin-Kashyrskyi district of Volyn region. Kamin-Kashyrskyi area has a flat terrain and is characterized by a warm temperate continental climate with sufficient amount of moisture, the presence of impoverished sod-podzolic soils. The area is mostly plain, with large marsh massifs, which are favorable conditions for the existence of Mamestra brassicae, as this species is moisture-loving. Observation of biocenotic connections in the agrobiocenoses of white cabbage and stationary research on the development of protection, testing and implementation systems was carried out during 2017-2018 at the garden sites of Kamin-Kashirsky district during the entire vegetation period of the plants. White cabbage is damaged throughout the period of vegetation, however, the damage that appear after emergence of seedlings and planting of seedlings into the soil are dangerous due to their consequences. In the second half of summer and in autumn, the larvae of Mamestra brassicae caused significant damage to cabbage plants in the gardens of Novi Chervyshcha. Within this area, Mamestra brassicae develops two generations per year, causing tangible damage to the agrocoenosis of cabbage of different sowing dates. The contamination of cabbage by the larva of the first and second generations approximately accounts to 24%, where 2-3 larvae live on one plant. The massive emergence of the imago occurs in the middle of May the first half of June while the average daily temperature is +20°С to +22°С. The first egg laying was recorded at the end of May, which the female lays in groups, 20-80 units on the underside of the leaves, and the embryonic development lasts 6 to 8 days. Pupae hibernate in the soil, at a depth of 8-12 cm. Significant damage to white cabbage plants was caused by the larvae of the first generation in June and early July, and of the second generation in August and early September. They intensively feed at night and at dawn, and in the daytime there is a decline in mobility and nutritional activity. Second-generation larvae often bite into cabbage heads where they make holes and pollute them with their liquid excrement, which leads to a decrease in crops. The use of microbiological drugs Dimilin and Insehar are some of the most effective ways to get rid of Lepidoptera, including larvae of Mamestra brassicae, which provide protection of cabbage plants by 93-97%.


Author(s):  
Elena Abella ◽  
Rosa García-Cerdá ◽  
Adolfo Marco

Egg fertilization rate is a defining event in the life history of reproducing oviparous species. However, for many terrestrial oviparous species, this parameter is only estimated after hatching, studying evidences of embryonic development in unhatched eggs. We compared the accuracy of this method with a second non-invasive technique based in the careful nest excavation within the first 96 hours after egg-laying and counting the proportion of eggs with a white spot in the shell. The study was conducted in a nesting population of loggerhead turtles (Caretta caretta) from Boavista Island (Republic of Cabo Verde). We found significant differences on the estimation of fertilization rate between both techniques. After hatching experimented researchers significantly overestimated the number of unfertilised eggs and this parameter was not correlated with the estimation after laying. The earlier estimation had no effect on hatching success and hatchling phenotype. There was no correlation between the number of alive embryos at laying and the hatching success. Unfertile eggs have no effect on survival of developing embryos withing a nest. Fertilization rate in loggerheads did not show spatial or temporal variation during nesting season. We proposed the implementation in sea turtle nesting monitoring programs of an annual, accurate and non-invasive estimation of egg fertilization rate based in the excavation of a sample of representative nests immediately after the formation of the white spot in the shell of developing embryos.


2018 ◽  
Vol 15 (4) ◽  
pp. e1010 ◽  
Author(s):  
Manuel López-Gómez ◽  
Soledad Verdejo-Lucas

Meloidogyne javanica has showed less reproductive success than M. incognita in watermelon genotypes. This study was conducted to elucidate the low reproduction of M. javanica in watermelon. The post-infection development of M. javanica in watermelon ‘Sugar Baby’ was determined at progressively higher initial population (Pi) levels at two time points during the life cycle. Plants were inoculated with 0, 25, 50, 100, 200, and 300 second-stage juveniles (J2)/plant. The increase in Pi was correlated with the penetration rates (R2= 0.603, p<0.001) and total numbers of nematodes in the root (R2 =0.963, p< 0.001) but there was no correlation between the Pi and the reproduction factor (eggs/plant/Pi). The population in the roots at 26 days post-inoculation (dpi) consisted primarily of third-stage juveniles (J3) with a small presence of J2 and fourth stages, and egg-laying females. The dominance of the J3, when egg-laying females are expected, point to the malfunction of the feeding sites that failed to support nematode development beyond the J3 stage. The similarities in egg-laying females at 26 and 60 dpi imply the disruption of the life cycle. Watermelon compensated for M. javanica parasitism by increasing vine length (19% to 33%) and dry top weight (40%) in comparison with the non-inoculated plants. The area under the vine length progress curve was significantly larger as the Pi progressively increased (R²=0.417, p<0.001). Physiological variation was detected between the M. incognita populations. M. arenaria had less ability to invade watermelon roots than did M. incognita and M. javanica.


Nematology ◽  
2020 ◽  
Vol 22 (5) ◽  
pp. 515-527 ◽  
Author(s):  
Natsumi Kanzaki ◽  
Taisuke Ekino ◽  
Noritoshi Maehara ◽  
Takuya Aikawa ◽  
Robin M. Giblin-Davis

Summary Bursaphelenchus acaloleptae n. sp. is described and figured based upon its morphological characters and molecular profiles. The new species belongs to the xylophilus-group of the genus and is typologically characterised by its secretory-excretory pore being located slightly posterior to the median bulb, weakly tapering, relatively broad and straight female tail with variously shaped terminus, and rounded male bursal flap with squared terminus. The new species is phylogenetically and biologically closest to B. luxuriosae. These cryptic species share the host (habitat) tree species, Aralia elata (Araliaceae), the same carrier insect species, Acalolepta luxuriosa (Cerambycidae), and a characteristic phoretic adult form. However, the new species is typologically distinguished from all other xylophilus-group species by the combination of the above-mentioned characters and molecular profiles (SSU and LSU molecular barcodes). Further, B. acaloleptae n. sp. can be distinguished from its closest relative, B. luxuriosae, by mating experiments, i.e., these two species did not produce a viable F1 generation in reciprocal crossings, thereby confirming separate species status using the biological species concept.


1988 ◽  
Vol 62 (01) ◽  
pp. 22-31 ◽  
Author(s):  
S. George Pemberton ◽  
Brian Jones ◽  
Gregory Edgecombe

Stromatoporoids from the Late Devonian (early Frasnian) Waterways Formation near Fort McMurray, Alberta, contain well preservedTrypanitesMägdefrau. The stromatoporoid heads are formed of an initial growth ofClathrocoilona inconstansStearn that is encased by a second stage growth ofTrupetostroma papulosumStearn. These two stages were separated by a period of no growth and erosion. The first two generations of boring penetrated the skeleton ofC. inconstanswhile the third generation borings penetrated bothC. inconstansandT. papulosum.The borings in the stromatoporoids are filled with light colored micrite, dark colored micrite, skeletal fragments, dolomite, non-ferroan calcite, and ferroan calcite. Analysis of the borings, the growth stages of the stromatoporoids, the boring fill, and the orientation of the geopetal fabrics indicates that the stromatoporoids were subjected to repeated cycles of growth-boring-filling and reorientation. This complex interaction of biologic and physical reworking had a profound influence on the diagenetic transformation of the stromatoporoid heads. This example clearly illustrates the role that biogenic agents can play in the production of diagenetic fabrics of hard carbonate substrates.


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