scholarly journals A Generalist Feeding on Brassicaceae: It Does Not Get Any Better with Selection

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 954
Author(s):  
Jacinta M. Zalucki ◽  
David G. Heckel ◽  
Peng Wang ◽  
Suyog Kuwar ◽  
Daniel G. Vassão ◽  
...  

Brassicaceae (Cruciferae) are ostensibly defended in part against generalist insect herbivores by toxic isothiocyanates formed when protoxic glucosinolates are hydrolysed. Based on an analysis of published host records, feeding on Brassicas is widespread by both specialist and generalists in the Lepidoptera. The polyphagous noctuid moth Helicoverpa armigera is recorded as a pest on some Brassicas and we attempted to improve performance by artificial selection to, in part, determine if this contributes to pest status. Assays on cabbage and kale versus an artificial diet showed no difference in larval growth rate, development times and pupal weights between the parental and the selected strain after 2, 21 and 29 rounds of selection, nor in behaviour assays after 50 generations. There were large differences between the two Brassicas: performance was better on kale than cabbage, although both were comparable to records for other crop hosts, on which the species is a major pest. We discuss what determines “pest” status.

2003 ◽  
Vol 67 (4) ◽  
pp. 477-490 ◽  
Author(s):  
Alberto García ◽  
Dolores Cortés ◽  
Teodoro Ramírez ◽  
Ana Giráldez ◽  
Ángel Carpena

Polar Biology ◽  
2009 ◽  
Vol 33 (5) ◽  
pp. 693-702 ◽  
Author(s):  
Mikaela Torp ◽  
Johan Olofsson ◽  
Johanna Witzell ◽  
Robert Baxter

2000 ◽  
Vol 76 (3) ◽  
pp. 249-259 ◽  
Author(s):  
N. G. PRASAD ◽  
MALLIKARJUN SHAKARAD ◽  
VISHAL M. GOHIL ◽  
V. SHEEBA ◽  
M. RAJAMANI ◽  
...  

Four large (n > 1000) populations of Drosophila melanogaster, derived from control populations maintained on a 3 week discrete generation cycle, were subjected to selection for fast development and early reproduction. Egg to eclosion survivorship and development time and dry weight at eclosion were monitored every 10 generations. Over 70 generations of selection, development time in the selected populations decreased by approximately 36 h relative to controls, a 20% decline. The difference in male and female development time was also reduced in the selected populations. Flies from the selected populations were increasingly lighter at eclosion than controls, with the reduction in dry weight at eclosion over 70 generations of selection being approximately 45% in males and 39% in females. Larval growth rate (dry weight at eclosion/development time) was also reduced in the selected lines over 70 generations, relative to controls, by approximately 32% in males and 24% in females. However, part of this relative reduction was due to an increase in growth rate of the controls populations, presumably an expression of adaptation to conditions in our laboratory. After 50 generations of selection had elapsed, a considerable and increasing pre- adult viability cost to faster development became apparent, with viability in the selected populations being about 22% less than that of controls at generation 70 of selection.


2020 ◽  
Vol 34 (8) ◽  
pp. 1577-1588
Author(s):  
Wataru Kojima ◽  
Tatsunori Nakakura ◽  
Ayumi Fukuda ◽  
Chung‐Ping Lin ◽  
Masahiro Harada ◽  
...  

2000 ◽  
Vol 78 (10) ◽  
pp. 1712-1722 ◽  
Author(s):  
Carlos D Camp ◽  
Jeremy L Marshall ◽  
Richard M Austin, Jr.

We investigated the possible role of environmental variables in determining body size within a complex of salamander species (Desmognathus quadramaculatus). We analyzed data generated from life-history studies on populations from throughout the range of this species complex. We incorporated an alternative-hypothesis framework (sensu Platt) to determine the better predictor of adult body size, age at maturity, or size at metamorphosis. We found that almost 90% of the variation in adult body size was explained by size at metamorphosis, which was determined by a combination of rate of larval growth and length of the larval period. Environmental temperature and moisture level were positively correlated with larval growth rate and length of the larval period, respectively. We propose a simple model of body-size evolution that incorporates both adaptive and plastic components. We suggest that the length of the larval period may adaptively respond to moisture-level predictability. In addition, we suggest that the response of the larval growth rate to temperature may be plastic. Because the selection pressure due to drying-induced mortality is pervasive among species of amphibians, it may have played a role in shaping body-size radiation in desmognathines as well as the ecological structure of Appalachian streamside communities.


1984 ◽  
Vol 41 (11) ◽  
pp. 1565-1569 ◽  
Author(s):  
T. C. Lambert ◽  
D. M. Ware

The spawning tactic of herring (Clupea harengus) wherein batches of eggs are deposited leading to a succession of larval cohorts is elaborated. We found the time interval between cohorts to be a function of larval growth rate as well as larval mouth size. In view of the relationship with growth rate we suggest a continuum of reproductive strategies with "bet hedging" by herring at one extreme and an "all at once" egg release by Atlantic mackerel (Scomber scombrus) at the other.


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