Observations on the biology ofCerambyx duxFaldermann in the Maltese Islands

1977 ◽  
Vol 67 (1) ◽  
pp. 107-117 ◽  
Author(s):  
L. J. Saliba

AbstractThe distribution and host-range ofCerambyx duxFald. are summarised, and the detailed life-history in Malta, where the hosts are apple and pear, is described. Collections of various stages from host material indicate that the duration of the complete life-cycle is three years, including a 26–28 month larval period. The number of larval instars is estimated at six. Egg survival is dependent on high humidity. The early months of larval activity are confined to the superficial regions of the trunk and main branches of the host, penetration of the sapwood and heartwood occurring later. No special air-holes appear to be constructed by the larva. No exit gallery is constructed, and the emerging adult makes use of the existing burrows, finally gnawing its way to the exterior. The period of emergence is short (8–10 days) and may be stimulated by rain. Adult life lasts about one month. The average number of eggs laid per female is approximately 13. The main predator onC. duxlarvae is the larva ofZeuzera pyrina(L.). This is confined to the lesser limbs of trees in Malta, but extends throughout the trees in Gozo, and has practically eliminatedC. duxfrom this island.

Author(s):  
J. B. Brown-Gilpin

The wide variety of reproductive patterns and behaviour in the many species of Nereidae already studied clearly justifies further research. But the life history of Nereis fucata (Savigny) is not only of interest from the comparative point of view. Its commensal habit (it occurs within shells occupied by hermit crabs) immediately gives it a special importance. This alone warrants a detailed study, particularly as no commensal polychaete has yet been reared through to metamorphosis and settlement on its host (Davenport, 1955; Davenport & Hickok, 1957). The numerous interesting problems which arise, and the experimental methods needed to study them, are, however, beyond the range of a paper on nereid development. It is therefore proposed to confine the present account to the reproduction and development up to the time when the larvae settle on the bottom. The complete life cycle, the mechanism of host-adoption, and related topics, will be reported in later papers.


2019 ◽  
Vol 286 (1911) ◽  
pp. 20191608 ◽  
Author(s):  
Lauren E. Powell ◽  
Robert A. Barton ◽  
Sally E. Street

Life history is a robust correlate of relative brain size: larger-brained mammals and birds have slower life histories and longer lifespans than smaller-brained species. The cognitive buffer hypothesis (CBH) proposes an adaptive explanation for this relationship: large brains may permit greater behavioural flexibility and thereby buffer the animal from unpredictable environmental challenges, allowing for reduced mortality and increased lifespan. By contrast, the developmental costs hypothesis (DCH) suggests that life-history correlates of brain size reflect the extension of maturational processes needed to accommodate the evolution of large brains, predicting correlations with pre-adult life-history phases. Here, we test novel predictions of the hypotheses in primates applied to the neocortex and cerebellum, two major brain structures with distinct developmental trajectories. While neocortical growth is allocated primarily to pre-natal development, the cerebellum exhibits relatively substantial post-natal growth. Consistent with the DCH, neocortical expansion is related primarily to extended gestation while cerebellar expansion to extended post-natal development, particularly the juvenile period. Contrary to the CBH, adult lifespan explains relatively little variance in the whole brain or neocortex volume once pre-adult life-history phases are accounted for. Only the cerebellum shows a relationship with lifespan after accounting for developmental periods. Our results substantiate and elaborate on the role of maternal investment and offspring development in brain evolution, suggest that brain components can evolve partly independently through modifications of distinct developmental phases, and imply that environmental input during post-natal maturation may be particularly crucial for the development of cerebellar function. They also suggest that relatively extended post-natal maturation times provide a developmental mechanism for the marked expansion of the cerebellum in the apes.


2012 ◽  
Vol 8 (3) ◽  
pp. 362-364 ◽  
Author(s):  
Andrew T. Kahn ◽  
Julianne D. Livingston ◽  
Michael D. Jennions

A poor start in life owing to a restricted diet can have readily detectable detrimental consequences for many adult life-history traits. However, some costs such as smaller adult body size are potentially eliminated when individuals modify their development. For example, male mosquitofish ( Gambusia holbrooki ) that have reduced early food intake undergo compensatory growth and delay maturation so that they eventually mature at the same size as males that develop normally. But do subtle effects of a poor start persist? Specifically, does a male's developmental history affect his subsequent attractiveness to females? Females prefer to associate with larger males but, controlling for body length, we show that females spent less time in association with males that underwent compensatory growth than with males that developed normally.


2000 ◽  
Vol 14 (6) ◽  
pp. 931 ◽  
Author(s):  
James K. Liebherr

Life history information and first instar egg bursters are compared for larvae of 25 species across the monophyletic radiation of Hawaiian Platynini (Coleoptera : Carabidae). The plesiotypic larval duration is approximately five weeks, with derived extension of the larval period having evolved during phylogenetic diversification of the radiation. This extension in larval duration is associated with vestigialisation of the metathoracic flight wings. Egg size is larger in those brachypterous species with slower developing larvae, reflecting pervasive ecological specialisation of these taxa in the isolated, favourable, and temporally stable habitats of Hawaiian montane forests. First instar egg bursters are also compared across these taxa, with evolution of a keel-like egg burster congruently defining a clade also characterised by longer larval duration and larger egg size. A functional linkage between egg burster configuration and egg size is rejected by lack of any association between egg size and egg burster type in the related genus Calathus. Such rejection does not reduce the value of the egg burster for phylogenetic inference. The ability to assess taxa for both life history traits and egg burster configuration argues for similar treatment of all such characters, both ecological and morphological, when estimating phylogeny.


2014 ◽  
Vol 281 (1796) ◽  
pp. 20141421 ◽  
Author(s):  
Aino Kalske ◽  
Anne Muola ◽  
Pia Mutikainen ◽  
Roosa Leimu

Inbreeding can profoundly affect the interactions of plants with herbivores as well as with the natural enemies of the herbivores. We studied how plant inbreeding affects herbivore oviposition preference, and whether inbreeding of both plants and herbivores alters the probability of predation or parasitism of herbivore eggs. In a laboratory preference test with the specialist herbivore moth Abrostola asclepiadis and inbred and outbred Vincetoxicum hirundinaria plants, we discovered that herbivores preferred to oviposit on outbred plants. A field experiment with inbred and outbred plants that bore inbred or outbred herbivore eggs revealed that the eggs of the outbred herbivores were more likely to be lost by predation, parasitism or plant hypersensitive responses than inbred eggs. This difference did not lead to differences in the realized fecundity as the number of hatched larvae did not differ between inbred and outbred herbivores. Thus, the strength of inbreeding depression in herbivores decreases when their natural enemies are involved. Plant inbreeding did not alter the attraction of natural enemies of the eggs. We conclude that inbreeding can significantly alter the interactions of plants and herbivores at different life-history stages, and that some of these alterations are mediated by the natural enemies of the herbivores.


2005 ◽  
Vol 273 (1587) ◽  
pp. 741-750 ◽  
Author(s):  
Barbara Taborsky

There is increasing evidence that the environment experienced early in life can strongly influence adult life histories. It is largely unknown, however, how past and present conditions influence suites of life-history traits regarding major life-history trade-offs. Especially in animals with indeterminate growth, we may expect that environmental conditions of juveniles and adults independently or interactively influence the life-history trade-off between growth and reproduction after maturation. Juvenile growth conditions may initiate a feedback loop determining adult allocation patterns, triggered by size-dependent mortality risk. I tested this possibility in a long-term growth experiment with mouthbrooding cichlids. Females were raised either on a high-food or low-food diet. After maturation half of them were switched to the opposite treatment, while the other half remained unchanged. Adult growth was determined by current resource availability, but key reproductive traits like reproductive rate and offspring size were only influenced by juvenile growth conditions, irrespective of the ration received as adults. Moreover, the allocation of resources to growth versus reproduction and to offspring number versus size were shaped by juvenile rather than adult ecology. These results indicate that early individual history must be considered when analysing causes of life-history variation in natural populations.


1976 ◽  
Vol 108 (9) ◽  
pp. 931-934 ◽  
Author(s):  
P. Martel ◽  
H. J. Svec ◽  
C. R. Harris

AbstractLaboratory studies on the biology of the carrot weevil, Listronotus oregonensis (LeConte), were performed at 21° and 27 °C. At 21 °C females laid eggs for 88 days on carrot slices and 94 days on foliage. Egg production per female averaged 156 and 175 on slices and leaves respectively. Eggs hatched after 8.3 days incubation and the larval stage comprising four instars was completed in 19.1 days. The prepupal and pupal stages lasted 3.7 and 9.4 days respectively. The complete life cycle including an average preoviposition period of 17 days was 57.6 days. Development was more rapid at 27 °C, with the complete life cycle taking only 37 days.


2017 ◽  
Vol 102 ◽  
pp. 36-41 ◽  
Author(s):  
Jincheng Zheng ◽  
Xiongbin Cheng ◽  
Ary A. Hoffmann ◽  
Bo Zhang ◽  
Chun-Sen Ma

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