scholarly journals REPRODUCTIVE ECONOMY IN THE CHALCIDOID WASP MELITTOBIA

Genetics ◽  
1947 ◽  
Vol 32 (1) ◽  
pp. 29-37
Author(s):  
R G Schmieder ◽  
P W Whiting
Author(s):  
Amanda Tracey

According to traditional theory, larger plants generaly have an advantage with respect to competition, especially for light. It seems a paradox then that most species that coexist within natural vegetation are relatively small; specis size distributions are right-skewed at virtually every scale. The critical question then becomes: if bigger is better in competition for resources, why then are there so many small plants? A potential explanation for this paradox is that smaller species may have greater reproductive economy-i.e. the ability to reproduce despite suppression from intense competition. Selection for greater reproductive economy may be associated with smaller seed sizes, increased rates of self-fertilization and/or clonality, and in the case of this study, smaller size at reproductive maturity. Random plots in an old field at Queen's University Biological Station were sampled and the largest and smallest reproductive individuals of each species were collected, dried and weighed - to test the hypothesis that smaller species can reproduce at a smaller proportion of their maximum potential plant sizes. The results did not support this, but the hypothesis that smaller plants have greater reproductive economy could not be rejected as it was not possible to record data for the largest possible plant size for each species (since even the largest plants were subjected to competition from neighbours). This provides a focus for future research. Understanding the role of plant size in affecting the process of species assembly has important implications for species coexistence and mechanisms of biodiversity preservation, and thus efforts involving conservation and ecosystem management.


1956 ◽  
Vol 187 (2) ◽  
pp. 347-352 ◽  
Author(s):  
David W. Bishop

Determinations of the rates of secretion and the pressures against which ligated, catheterized oviducts of Dial-urethane-anesthetized rabbits produce tubal fluid indicate this to be an active secretion of the genital tract. Secretory activity is influenced by the hormonal condition of the animal. Both secretory rate and pressure are high during estrus (av., 0.79 ml/24 hr/tube and 46.0 cm H2O pressure) and low in late pregnancy (0.28 ml/24 hr/tube and 9.6 cm H2O pressure). Secretory activity is severely reduced after castration (0.14 ml/24 hr/tube and 11.8 cm H2O pressure), but this decrease can be counteracted by administration of estradiol benzoate (5 γ/day for 3 days). The secretory process is stimulated by pilocarpine (1.11 ml/24 hr/tube and 71.3 cm H2O pressure). The oviduct secretion may be considered to play a vital role in the reproductive economy of the rabbit.


1857 ◽  
Vol 3 ◽  
pp. 454
Author(s):  
Goodsir

In a recent work, entitled “Wahre Parthenogenesis bei Schmetterlingen und Bienen”—Real Parthenogenesis in Butterflies and Bees, Von Siebold, after reviewing the present condition of the subject, distinguishes the so-called alternate generation from parthenogenesis, and limits Professor Owen's term to reproduction by unimpregnated females.He has ascertained that this real parthenogenetic mode of reproduction occurs in certain moths—Solenobia lichenellaandtriquetrella, the larvæ of which are sac-bearers; and inPsyche helix, the larva of which constructs one of those remarkable spiral sacs which have been mistaken for the shells of molluscs.


Parasitology ◽  
1930 ◽  
Vol 22 (3) ◽  
pp. 361-369
Author(s):  
Enid K. Sikes

The Chalcidoid wasp, Bairamlia fuscipes, was found parasitising the flea Ceratophyllus wickhami in the nest of the North American Grey Squirrel (Sciurus carolinensis) from Gerrard's Cross.The larval and pupal stages of B. fuscipes were found in the cocoons of C. wickhami, and the adults were crawling about in the squirrel's nest.The parasites were scarce, only 7 per cent, of the cocoons dissected at intervals during fifteen months were parasitised.The parasite has not been reared in the laboratory beyond the second instar larva, though full grown larvae have successfully reached maturity under experimental conditions.B. fuscipes oviposits through the flea cocoon and fixes the egg on the abdomen of a resting larva or pupa. Only one egg has been found in each parasitised cocoon. The larva feeds externally on the flea, fixing itself to the fourth abdominal segment or thereabouts.Attempts were made to parasitise larvae of Xenopsylla astia, but without success.The external anatomy of the full grown larva of B. fuscipes is described.


1979 ◽  
Vol 111 (4) ◽  
pp. 421-424 ◽  
Author(s):  
Carl M. Yoshimoto ◽  
Gary A. P. Gibson

An interesting, highly unusual chalcidoid wasp was found recently for Dr. L. Masner in material collected for him by Mr. F. M. Oliveira from Brazil. This unique specimen proved to belong to an undescribed genus in the subfamily Aximinae of the family Eurytomidae. It keys to the genera Axima Walker and Conoaxima Brues in Burks’ (1971) key to the genera of Eurytomidae, but differs in a number of morphological characters discussed below.The structure and sculpture of this unique female specimen are illustrated by scanning electron photographs, the wings and antennae by macrophotography.


2019 ◽  
Vol 80 ◽  
pp. 239-246
Author(s):  
Simon Haarder ◽  
Csaba Thuróczy ◽  
György Csóka
Keyword(s):  

Aprostocetus eriophyes (Taylor, 1909) (Hymenoptera: Eulophidae) is reported as new to the Hungarian fauna. Female specimens were reared from galls of the hazelnut big bud mite (Phytoptus avellanae Nalepa, 1889) (Phytoptidae) collected in February to April 2017 at six different locations in Hungary. Diagnosis, hosts, biology and distribution of A. eriophyes is discussed. With 3 figures.


1986 ◽  
Vol 118 (3) ◽  
pp. 249-254 ◽  
Author(s):  
J.D. Shorthouse ◽  
A. West ◽  
R.W. Landry ◽  
P.D. Thibodeau

AbstractThe chalcidoid wasp, Hemadas nubilipennis (Ashmead), induces a reniform gall on the adventitious shoots of lowbush blueberry. Eggs are laid within shoot tissues 5–15 mm below the tip and then the female destroys the apex of the shoot by stabbing with her ovipositor. Stabbing terminates growth of the shoot, and as a result all nutrients flowing into the shoot are redirected towards the gall tissues and larvae. This is a rare example of an insect damaging tissues of the host plant for the benefit of the offspring. It also is suggested that stabbing and gall formation have a pruning effect on the host plant.


Author(s):  
V. Rubel

The stories of paradise garden, first men living in it, their fall and exile from Eden are fixed in the Bible and considered a sphere of religious and mythological, but not a historical component of the Holy Scripture. Textual analysis of the second chapter of «The Book of Genesis» gives grounds to consider Eden a real geographical object, which limits correspond to the territories of today’s Tabriz Valley. Description of paradise garden, where Adam, created by God, was not aware of death and was richly fed, not making any additional efforts, is a peculiar human memory of an era of early pre-Neolithic being. «The exile from Eden» – is an era in history, when «unproblematic» life of primitive men was finished because of lack of the natural resourses, quantity of which was deficient for survival. It made people to occupy territories beyond the original range of their existence. The second result of «the exile from paradise» was a curse of Adam, as since then he had to get food «by the sweat of his brow». Modern scientific terminology calls it «Neolithic revolution», i.e. transition from the foraging to the agriculture, when human had to master the art of tilling for growing food. Inverse chronological calculation method of generations of biblical patriarchs allows to date this historical fracture by the first half – the middle of III millennium BC. The third result of «the exile from paradise» was declared loss of human’s immortality. The emergence of reproductive economy, when a person began to plow the ground, dig channels, build dams, pasture livestock and in such way «get the daily bread», intensified the development of protoscientific knowledge, which resulted in human’s awareness of finality of his personal physical existence. The Bible redefines this fact as the loss of «eternity» by human.


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