The reproductive life history of the predacious, sand-burrowing mayfly Dolania americana (Ephemeroptera: Behningiidae) and comparisons with other mayflies

1991 ◽  
Vol 69 (4) ◽  
pp. 1083-1093 ◽  
Author(s):  
Thomas J. Fink ◽  
Tomás Soldán ◽  
Janice G. Peters ◽  
William L. Peters

Oogenesis in Dolania is unique among Ephemeroptera, with one oocyte developing per ovariole, low numbers of ovarioles, and routine resorption of one-third to one-half of ovarioles. Fecundity is 20 times smaller than in mayflies from other families, and mature egg dry weight is approximately 32 times the values of non-Behningiidae mayflies. Seventy percent of the linear growth of maturing oocytes occurs in a 2- to 3-week period during the late penultimate to early final larval stadia. The gut does not atrophy fully, and nonmaturing oocytes remain small and are not resorbed until the other oocytes reach maturity. Thus, resorbing oocytes are probably not an important energy source for the maturing oocytes. Starvation can further reduce Dolania fecundity from a normal 100 eggs to 6. Limited oocyte resorption appears common in mayflies. Callibaetis ferrugineus female imagos, which are ovoviviparous, resorb much of their abdominal muscle. Some ovulation and even egg development may occur in the adult stage of many oviparous species. The thick chorion and thick, sticky fibrous suprachorionic layer of Dolania's egg probably resist damage from sand and fungi for nearly 1 year in a coarse rolling sand habitat. The large egg produces a well-developed first-instar larva 2.5–5 times the length of any other mayfly first instar. The reproductive strategy of Dolania and Behningia, unlike that of other mayflies, is to produce large eggs and thereby large predatory early-instar larvae capable of exploiting a large size range of prey.

2014 ◽  
Author(s):  
Bruno A S de Medeiros ◽  
Daniela C Bená ◽  
Sergio A Vanin

Weevils are one of the largest groups of living organisms, with more than 60,000 species feeding mostly on plants. With only one exception, their described larvae are typical plant-feeders, with mouthparts adapted to chewing plant material. Here we describe the second case of a weevil with early-instar larvae adapted to killing conspecifics. We have studied the life history of Anchylorhynchus eriospathae G. G. Bondar, 1943, a species whose immatures feed internally on palm flowers and fruits. We provide detailed descriptions of all immature stages, including the extremely modified first-instar larva. Unlike other weevils and later instars, this stage exhibits a flat body with very long ventropedal lobe setae, a large and prognathous head with a gula, and falciform mandibles, each with a serrate retinaculum, that are used to fight with and eventually kill other first-instar larvae. We also provide biological notes on all stages and the results of behavioral tests that showed that larval aggression occurs only among early life stages. Finally we show that adult size is highly dependent on timing of oviposition. This specialized killer first instar probably evolved independently from the one other case known in weevils (in Revena rubiginosa). Interestingly, both lineages inhabit the same hosts, raising the possibility that both intra- and inter-specific competition shaped those phenotypes. Given the scarcity of knowledge on early larval stages of concealed insect herbivores, it is possible that our findings represent an instance of a much broader phenomenon. Our observations also allowed us to conclude that Anchylorhynchus eriospathae and A. hatschbachi G. G. Bondar, 1943 are actually the same species, which we synonymize here by considering the latter as a junior synonym (new synonymy).


2014 ◽  
Author(s):  
Bruno A S de Medeiros ◽  
Daniela C Bená ◽  
Sergio A Vanin

Weevils are one of the largest groups of living organisms, with more than 60,000 species feeding mostly on plants. With only one exception, their described larvae are typical plant-feeders, with mouthparts adapted to chewing plant material. Here we describe the second case of a weevil with early-instar larvae adapted to killing conspecifics. We have studied the life history of Anchylorhynchus eriospathae G. G. Bondar, 1943, a species whose immatures feed internally on palm flowers and fruits. We provide detailed descriptions of all immature stages, including the extremely modified first-instar larva. Unlike other weevils and later instars, this stage exhibits a flat body with very long ventropedal lobe setae, a large and prognathous head with a gula, and falciform mandibles, each with a serrate retinaculum, that are used to fight with and eventually kill other first-instar larvae. We also provide biological notes on all stages and the results of behavioral tests that showed that larval aggression occurs only among early life stages. Finally we show that adult size is highly dependent on timing of oviposition. This specialized killer first instar probably evolved independently from the one other case known in weevils (in Revena rubiginosa). Interestingly, both lineages inhabit the same hosts, raising the possibility that both intra- and inter-specific competition shaped those phenotypes. Given the scarcity of knowledge on early larval stages of concealed insect herbivores, it is possible that our findings represent an instance of a much broader phenomenon. Our observations also allowed us to conclude that Anchylorhynchus eriospathae and A. hatschbachi G. G. Bondar, 1943 are actually the same species, which we synonymize here by considering the latter as a junior synonym (new synonymy).


1984 ◽  
Vol 116 (7) ◽  
pp. 913-917 ◽  
Author(s):  
D. B. Smith ◽  
M. K. Sears

AbstractAlthough Plutella porrectella (L.) is similar in appearance to the diamondback moth, P. xylostella (L.), several aspects of its biology are quite different from its more common relative. P. porrectella completed two generations per year and overwintered as an early-instar larva within apical buds of dame's rocket, Hesperis matronalis (L.). Four instars were observed in larvae reared in the laboratory. An average of 30 days was required for completion of one generation at 25 °C. This species does not seem to be an alternative host for parasites of the diamondback moth as only a single parasitic wasp, Itoplectis conquisitor (Say), was reared from 228 larvae collected in the field.


1950 ◽  
Vol 41 (2) ◽  
pp. 429-438 ◽  
Author(s):  
Ewen Cameron

While investigating the biological control of certain Hepialids, a very interesting Ichneumonid parasite, Alomya debellator (F.) was reared from the pupae of the Swift Moth, Hepialus lupulinus (L.).The systematic position of this parasite has been thoroughly investigated and the members of the special sub-family, Metopiinae, to which it has been assigned, are characterised by the possession of only one trochanter on each foreleg. A. debellator is the sole representative of the tribe Alomyini.After extensive collecting, and a thorough search of the literature, the conclusion has been reached that the distribution of this parasite is fairly local, but its range in Great Britain and certain other European countries is wide. As a result of the present study H. lupulinus has been definitely proved to be the host of A. debellator.A fairly full account of the life-history of the parasite has been worked out, and amongst other things, a point of special interest is the arrest in development which occurs in the first-instar larva. Possible explanations of this phenomenon are discussed.The morphological and anatomical structure of the larva have been fully investigated and described, and useful diagnostic characteristics both for the primary and mature larval stages, have been discovered.The paper concludes with a discussion on the potential value of A. debellator as a factor in the control of H. lupulinus, and other allied species belonging to the genus Oncopera in Australia. It is maintained, on the evidence collected, that this parasite in some areas is probably the most important single factor of biological control. A note on the feeding habits of Hepialids, and a few remarks about the collecting of parasitised material are appended. Altogether some 7,000 specimens of H. lupulinus larvae and pupae many of which were parasitised by A. debellator were collected from the Willingham area of Cambridgeshire.


1983 ◽  
Vol 61 (3) ◽  
pp. 586-596 ◽  
Author(s):  
Vytenis Gotceitas ◽  
Hugh F. Clifford

Dicosmoecus atripes (Hagen) has a 2-year life cycle in Dyson Creek, Alberta, a second order foothills stream of the eastern Canadian Rockies. Emergence and oviposition occur from August to mid-October. The first winter is spent as first instar larvae, the second as inactive fifth (final) instars in a form of diapause. No growth was observed in overwintering first instar larvae, and a significant (P < 0.05) weight loss was recorded in overwintering fifth instar larvae. Temperature seems to be the most important factor responsible for the 2-year life cycle. Annual production was estimated at 91.4 mg∙m−2∙year−1, with an annual production and biomass turnover (P/B) ratio of 4.97. Larval diet and microhabitat changed between instars. The proportion of diatoms in the diet of early instar larvae was significantly (P < 0.001) greater than that of third and later instars. Early instar larvae inhabit stream margins, while larvae of third and later instars were mainly found in midstream reaches. Larvae of all instars preferred pools to riffles. Abiotic factors important in microhabitat selection seemed to differ between larval instars.


2019 ◽  
Vol 25 (1) ◽  
Author(s):  
Danielle Whiting ◽  
Ian Rudd ◽  
Amit Goel ◽  
Seshadri Sriprasad ◽  
Sanjeev Madaan

Abstract Background Angiomyolipomas are rare mesenchymal tumours arising from the perivascular epithelioid cells consisting of variable amounts of adipose, thick-walled blood vessels and smooth muscle cells. These benign tumours commonly occur in the kidney with only a few case reports of adrenal angiomyolipomas which have the potential to reach a large size and haemorrhage. Case presentation A 45-year-old lady presented with a 3-week history of right loin pain, nausea and vomiting. A CT scan revealed a right adrenal angiomyolipoma measuring 6.3 × 6.8 cm with associated haemorrhage. The lesion was successfully treated with right open adrenalectomy, and histology confirmed the diagnosis of adrenal angiomyolipoma. The patient remained well with no evidence of recurrence at the 36-month follow-up. Conclusion Adrenal angiomyolipomas are rare benign tumours that have the ability to reach a large size and potential to bleed. Here, we report the second case of spontaneous haemorrhage in an adrenal angiomyolipoma, which was successfully treated with open adrenalectomy.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Krzysztof Szpila ◽  
Kinga Walczak ◽  
Nikolas P. Johnston ◽  
Thomas Pape ◽  
James F. Wallman

AbstractThe first instar larva of a species of the Australian endemic genus Aenigmetopia Malloch is described for the first time, along with the first instar larvae of three other Australian species representing the genera Amobia Robineau-Desvoidy and Protomiltogramma Townsend. Larval morphology was analysed using a combination of light microscopy, confocal laser scanning microscopy and scanning electron microscopy. The following morphological structures are documented: pseudocephalon, antennal complex, maxillary palpus, facial mask, modifications of thoracic and abdominal segments, anal region, spiracular field, posterior spiracles and details of the cephaloskeleton. Substantial morphological differences are observed between the three genera, most notably in the labrum and mouthhooks of the cephaloskeleton, sensory organs of the pseudocephalon, spinulation, sculpture of the integument and form of the spiracular field. The first instar larval morphology of Aenigmetopia amissa Johnston, Wallman, Szpila & Pape corroborates the close phylogenetic affinity of Aenigmetopia Malloch with Metopia Meigen, inferred from recent molecular analysis. The larval morphology of Amobia auriceps (Baranov), Protomiltogramma cincta Townsend and Protomiltogramma plebeia Malloch is mostly congruent with the morphology of Palaearctic representatives of both genera.


1981 ◽  
Vol 29 (1) ◽  
pp. 81 ◽  
Author(s):  
B Lamont

Kingia australis, common in the heaths and forests of south-western Australia, is distinguished from all other grass trees in Australia by the presence of a mantle of concealed aerial roots. A ring of up to 50 root primordia is initiated in winter from the stem apex. In plants more than 1 m high, initiation and commencement of elongation of the primary roots are no longer annual but dependent on the fire history of the plant. These roots descend between the stem and persistent leaf bases at about 2 cm per growing month, sending many lateral branches among the leaf bases. Aerial roots gradually replace the space occupied by the leaf bases until they may account for 45% of the dry weight of the aerial caudex. The caudex of one 6-m-high specimen bore up to 27 roots per cm2 transection of the root mantle, with about 3000 primary roots entering the soil. All underground primary roots (except the initial contractile roots) have an aerial origin and are concentrated vertically under the canopy. After 300-400 years the stem starts to die back from the base, and the aerial roots attached to that portion disintegrate. By propping up the stem and bridging the dead zone of the stem, the living aerial roots greatly extend the potential height and longevity of the plant. In addition, the hairy laterals are ideally located to absorb water and nutrients directly from the leaf bases. Protective and aerating functions are also indicated.


Zootaxa ◽  
2017 ◽  
Vol 4238 (4) ◽  
pp. 451 ◽  
Author(s):  
ALBERT DELER-HERNÁNDEZ ◽  
JUAN A. DELGADO

Preimaginal stages of the six species of Hydraenidae presently known from Cuba were obtained by rearing adults in the laboratory. Eggs of Hydraena perkinsi Spangler, 1980, H. decui Spangler, 1980 and H. franklyni Deler-Hernández & Delgado, 2012 are described and illustrated for the first time. The first instar larva of Gymnochthebius fossatus (LeConte, 1855) is redescribed, adding some new remarkable morphological characters including what could be the first abdominal egg-burster reported for this family. All larval instars of H. perkinsi, H. guadelupensis Orchymont, 1923 and Ochthebius attritus LeConte, 1878 are described and illustrated for the first time, with a special emphasis on their chaetotaxy. The second instar larva of G. fossatus along with first and third instar larvae of H. decui and H. franklyni are also studied for the first time. The pupal morphology and vestiture of a species belonging to the genus Hydraena are described for the first time, based on the pupa of H. perkinsi. Biological notes for several preimaginal stages of the studied species are also given. 


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