Methods for estimating and modelling spruce budworm development rates at constant temperatures

2021 ◽  
Vol 154 ◽  
Author(s):  
A.A. Wardlaw ◽  
K. Perrault ◽  
A.D. Roe ◽  
J. Dedes ◽  
C.L. Irwin ◽  
...  

Abstract We describe an experimental protocol for measuring the response of spruce budworm postdiapause larval development to temperature. This protocol is specifically designed to include measurements of development near their upper and lower thermal thresholds. The application of this protocol to a laboratory colony allowed for the first experimental evidence that spruce budworm larval development occurs at temperatures as low as 5 °C and as high as 35 °C, and it provides data to fit stage-specific development models. Our protocol is also designed to minimise mortality near the thermal development thresholds, thus allowing for multigenerational studies. We observed developmental plasticity in larvae reared at constant temperatures, particularly the occurrence of up to 42% of some individuals requiring only five instars to complete development compared to the expected six instars. The occurrence exhibited no clear relation to temperature. Although this protocol is specifically designed for spruce budworm, it provides a template for the study of other species’ developmental responses to temperature.

2007 ◽  
Vol 274 (1612) ◽  
pp. 977-981 ◽  
Author(s):  
Joel G Kingsolver

The tobacco hornworm Manduca sexta has been an important model system for understanding physiological control of growth, development and metamorphosis of insects for more than half a century. Like all Manduca , M. sexta typically has five larval instars, with developmental commitment to metamorphosis occurring early in the 5th (final) instar. Here we show that M. sexta from a field population in North Carolina (USA) shows substantial intraspecific variation in the number of larval instars when feeding on a modified artificial diet. Individuals with six instars consistently exhibited slower growth rates during early larval development than individuals with five instars. The frequency of individuals with six instars decreased with increased rearing temperature. In contrast, M. sexta from a laboratory colony consistently had five instars, and had more rapid larval growth rates than M. sexta from the field. We identify a threshold body size at the start of the 5th instar that predicts whether an individual will have five (greater than 600 mg) or six instars (less than 600 mg). Variation in field populations in Manduca provides an important resource for understanding physiological control, developmental plasticity and evolution of growth rate, body size and instar number.


1983 ◽  
Vol 115 (9) ◽  
pp. 1109-1117 ◽  
Author(s):  
G. T. Harvey

AbstractLaboratory studies of the mean weights of initial eggs (Ei) of the spruce budworm, Choristoneura fumiferana (Clem.), show that this value is determined by the genetic constitution of the female moth and is relatively independent of environmental control. Dietary differences experienced by the female during larval development, and originating from different hosts or from reduced nutrient levels in artificial diets, did not affect Ei values; however, depletion of nutrients sufficient to reduce fertility greatly did reduce Ei. Temperature conditions during the ultimate larval and pupal stages influence Ei values which vary inversely. Mean egg weights are strongly heritable and are readily selected for, thereby demonstrating the presence of strong genetic control.


1969 ◽  
Vol 101 (12) ◽  
pp. 1269-1285 ◽  
Author(s):  
F. T. Bird

AbstractCytoplasmic polyhedrosis viruses are, in general, more infectious to spruce budworm, Choristoneura fumiferana (Clemens), and forest tent caterpillar, Malacosoma disstria (Hübner), than the nuclear polyhedrosis viruses which affect these insects. The cytoplasmic polyhedrosis viruses interfere with and retard development of the nuclear polyhedrosis viruses.Larvae of both insects, as they grow older, develop resistance to both viruses. Resistance develops more rapidly and to a greater degree against the nuclear polyhedrosis than against the cytoplasmic polyhedrosis viruses.The nuclear polyhedrosis viruses are more lethal than the cytoplasmic polyhedrosis viruses, and all larvae infected with the nuclear polyhedrosis viruses die except those infected so late in larval development that they are able to pupate. Most young larvae infected with the cytoplasmic polyhedrosis virus die or are seriously affected, but infection has progressively less effect as the larvae mature.


1974 ◽  
Vol 48 (3) ◽  
pp. 161-165 ◽  
Author(s):  
Pakeer Oothuman ◽  
M. G. Simpson ◽  
B. R. Laurence

AbstractThe morphology of abnormal development of the filarial worm Brugia patel in a mosquito host, Anopheles labranchiae atroparvus, is described. Development was very variable, from little growth beyond the microfilarial stage to the complete development of two infective stage larvae in one mosquito. The majority of larvae developed beyond the microfilarial stage but integrated differentiation did not occur. In the most bizarre larval development, the intestinal and the rectal cells prolapsed and then attempted to differentiate outside the body of the filarial larva. It is concluded that the abnormal development of the filarial larvae in this mosquito host is due to the host reaction elicited by the developing larvae, apparent as melanisation 48–78 hours after ingestion by the mosquito, often localised specifically over the excretory and anal vesicles.


2019 ◽  
Vol 286 (1909) ◽  
pp. 20191315 ◽  
Author(s):  
Kimberley J. Simpson ◽  
Jill K. Olofsson ◽  
Brad S. Ripley ◽  
Colin P. Osborne

Coping with temporal variation in fire requires plants to have plasticity in traits that promote persistence, but how plastic responses to current conditions are affected by past fire exposure remains unknown. We investigate phenotypic divergence between populations of four resprouting grasses exposed to differing experimental fire regimes (annually burnt or unburnt for greater than 35 years) and test whether divergence persists after plants are grown in a common environment for 1 year. Traits relating to flowering and biomass allocation were measured before plants were experimentally burnt, and their regrowth was tracked. Genetic differentiation between populations was investigated for a subset of individuals. Historic fire frequency influenced traits relating to flowering and below-ground investment. Previously burnt plants produced more inflorescences and invested proportionally more biomass below ground, suggesting a greater capacity for recruitment and resprouting than unburnt individuals. Tiller-scale regrowth rate did not differ between treatments, but prior fire exposure enhanced total regrown biomass in two species. We found no consistent genetic differences between populations suggesting trait differences arose from developmental plasticity. Grass development is influenced by prior fire exposure, independent of current environmental conditions. This priming response to fire, resulting in adaptive trait changes, may produce communities more resistant to future fire regime changes.


Author(s):  
Hisanori Kohtsuka ◽  
Hiroaki Nakano

The development and growth of a feather star Decametra tigrina from Notojima Island, Japan, is reported. This is the first record describing the complete development, from early embryos to juveniles, in the family Colobometridae. Their larval development was observed to progress independently from the adults, and was similar to other feather star species. Embryos hatched as uniformly ciliated gastrulae, which turned into doliolaria larvae when four narrow circumferential ciliated bands were formed. Skeletal ossicles began to form inside the doliolaria larvae, which subsequently settled to the substrate, proceeding to the cystidean stage. The protrusion of the arms from the oral opening marked the beginning of the pentacrinoid stage. About 45 days after hatching, they autotomized their stalks and became juvenile comatulids with arms about 6 mm long. These early juveniles apparently differ from the adults in morphological characters, such as having no pairs of tubercles or spines on the dorsal of their cirrals, and no proximal pinnules except for the first pinnule (P1). Both features are prominent in adults and are used for the classification of D. tigrina. Morphological differences between juveniles and the adults may also occur in other feather star species. A revision of the classification of comatulids, which considers morphological changes with growth, is required.


2010 ◽  
Vol 47 (4) ◽  
pp. 690-694 ◽  
Author(s):  
E. Martins ◽  
J. A. Neves ◽  
T. C. Moretti ◽  
W.A.C. Godoy ◽  
P. J. Thyssen

Abstract Ornidia obesa F. (Diptera: Syrphidae) is usually neglected in forensic entomology, although adults are rather frequent on vertebrate carrion. In this study, conducted in southeastern Brazil in 2008, we used two pig carcasses, one killed by cocaine overdose and the other by shooting, to evaluate mainly the possible influences of the type of death on the larval development of O. obesa in the pig remains. We recorded the breeding of 218 adult specimens of this syrphid fly from the carcass killed by shooting, and none from the carcass killed by cocaine. These observations may open a new perspective for the use of O. obesa in forensic studies, considering its breeding preferences and its complete development on vertebrate carrion.


1986 ◽  
Vol 118 (1) ◽  
pp. 37-41 ◽  
Author(s):  
J.C. Bergh ◽  
W.D. Seabrook

AbstractSection 7 of the primary simplex of the ductus ejaculatorius of unmated male spruce bud worm moths, Choristoneura fumiferana, contains a yellow substance that is not present in recently mated males. The yellow substance occurs in laboratory-colony males reared on diet and in feral males reared on foliage. It is shown that the presence/absence of this material is a reliable index of copulation during the previous 24 h. Although the yellow substance regenerates over a period of several days, males 0–72 h post-copulation may be indexed when compared with unmated males of similar age.


2017 ◽  
Author(s):  
Derek W. R. White

AbstractHigher plants utilise developmental plasticity to adapt to changes in the environment, especially to variations in light. Much of this change in growth and development involves the light-mediated regulation of multiple hormone pathways. However, despite considerable progress towards understanding the molecular processes controlling light signalling and hormone activity, regulatory mechanisms preventing exaggerated plant developmental responses are not well understood. Here I report that the PPD regulatory complex has a crucial role in limiting developmental plasticity in Arabidopsis. Reductions in PPD or KIX8/9 gene expression resulted in; tolerance to ABA inhibition of seed germination, hypocotyl elongation, increases in stomata on hypocotyls, cambial cell proliferation and seed weight, and delayed flowering. Transcript profiling and analyses of hormone responses and genetic interactions established PPD modulates developmental plasticity, mainly by a combination of transcriptional activation and repression of genes controlling CRY/PHY light signalling and ABA, auxin, brassinosteroid, cytokinin and gibberellin homeostasis.


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