Temperature modulation of photoperiodism and the timing of late-season changes in life history for an aphid, Acyrthosiphon pisum

2011 ◽  
Vol 143 (1) ◽  
pp. 56-71 ◽  
Author(s):  
M.A.H. Smith ◽  
P.A. MacKay ◽  
R.J. Lamb
Keyword(s):  
Sexual Reproduction ◽  
Seasonal Changes ◽  
Acyrthosiphon Pisum ◽  
Late Summer ◽  
Day Length ◽  
Temperature Modulation ◽  
Four Seasons ◽  
Aphid Clone ◽  
Photoperiodic Responses

AbstractWhere winters are severe, aphids reproduce parthenogenetically and viviparously in summer, switch to sexual reproduction in late summer, and produce winter-hardy eggs by the end of the season. The role of day length and temperature in initiating seasonal changes from parthenogenetic to sexual reproduction by pea aphids, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae), are described and the selection pressures that affect the timing of this transition are investigated. Over four seasons, a pea aphid clone was sampled from field cages through late summer in southern Manitoba, Canada, and reared in the laboratory to determine the phenotypes of progeny produced as the season progressed. The timing of transitions from one phenotype to another under natural day length and temperature, and the critical day lengths that caused the transitions, coincided with expectations from laboratory studies of photoperiodic responses. Males and mating females appeared later when the weather in August was warm than when it was cool. The timing of seasonal changes was adapted to minimize the physiological time to the end of the season, which maximized the number of asexual summer generations. Ambient temperature modulated the response to day length and fine-tuned the timing of sexual reproduction to adapt for annual variation in autumn weather.

Temperature modulation of photoperiodism: an adaptation for long-distance dispersal in the aphid, Acyrthosiphon pisum (Hemiptera: Aphididae)

2013 ◽  
Vol 145 (3) ◽  
pp. 302-316
Author(s):  
M.A.H. Smith ◽  
P.A. MacKay ◽  
R.J. Lamb
Keyword(s):  
Acyrthosiphon Pisum ◽  
Seasonal Pattern ◽  
Local Population ◽  
Late Summer ◽  
Photoperiodic Response ◽  
Day Length ◽  
Temperature Modulation ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Critical Photoperiod

AbstractVariation in the seasonal occurrence of asexual and sexual phenotypes of Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae) is quantified for a local population in southern Manitoba, Canada. To survive winter, summer asexual generations must produce a sexual generation in a timely way at the end of the season, so that females can lay overwintering eggs. This transition is controlled by day length, which varies in a fixed seasonal pattern with latitude, and the local pattern of day length selects for an appropriate photoperiodic response. Substantial variation in the timing of production of males and mating females occurs among locally collected genotypes. Some of the variation is due to the arrival of long-distance dispersers (1000 km or more), and some is consistent with shorter but still long-distance dispersal. Some of the variation is due to year-to-year changes in late summer temperature. The critical day length in nature, which corresponds to critical photoperiod, increases as the average temperature decreases. This temperature modulation is adaptive because it allows many genotypes to produce some sexual phenotypes before the end of the season, although their photoperiodic responses are characteristic of long-distance dispersers and inappropriate to local day lengths.

Photorefractoriness and seasonal changes in the brain in response to changes in day length in American goldfinches (Carduelis tristis)

2002 ◽  
Vol 80 (12) ◽  
pp. 2100-2107 ◽  
Author(s):  
Regan H Marsh ◽  
Scott A MacDougall-Shackleton ◽  
Thomas P Hahn
Keyword(s):  
Seasonal Changes ◽  
Late Summer ◽  
Day Length ◽  
Free Living ◽  
Strong Trend ◽  
Carduelis Tristis ◽  
Song Control System ◽  
Song Control ◽  
Seasonally Breeding ◽  
The Brain

We examined neural and gonadal responses to photoperiod in a late-summer-breeding finch, the American goldfinch (Carduelis tristis). First we measured seasonal changes in the gonads of free-living goldfinches. Next we determined whether the gonads of goldfinches held on constant long days would eventually regress spontaneously. Finally, we compared the hypothalamic gonadotropin-releasing hormone (GnRH) system and song-control system of breeding and postbreeding birds. The results confirm that the gonads of wild goldfinches regress in late summer and show that the gonads of goldfinches held on constant long days regress spontaneously. Thus, according to at least one criterion, goldfinches become photorefractory, like other seasonally breeding songbirds. As well, goldfinches exhibited similar seasonal changes in the brain to spring-breeding birds. There was a decrease in GnRH immunoreactivity in autumn and a strong trend towards a reduction in the size of song-control regions (although this was statistically significant for only one area). Thus, although goldfinches breed late in summer as day length declines, some of their physiological responses to changes in photoperiod are similar to those that occur in spring-breeding songbirds.

Seasonal changes in leaf and stem loline alkaloids in meadow fescue

2011 ◽  
Vol 62 (3) ◽  
pp. 261 ◽  
Author(s):  
Brian Patchett ◽  
Ravi Gooneratne ◽  
Lester Fletcher ◽  
Bruce Chapman
Keyword(s):  
Seasonal Changes ◽  
Seasonal Pattern ◽  
Late Summer ◽  
Early Spring ◽  
Early Summer ◽  
Sharp Decline ◽  
Meadow Fescue ◽  
Accumulation Pattern ◽  
Loline Alkaloids

Leaf and stem loline alkaloid concentration in 10 European meadow fescue (Festuca pratensis Huds.) lines grown in a field in Canterbury, New Zealand, were determined in samples collected six times between early spring 2004 and late autumn 2005. Significant differences in loline alkaloid concentrations were noted between lines and between harvest times. Higher total loline alkaloid concentrations (up to 4990 µg g–1) were found in stems compared to leaf (up to 1770 µg g–1). However, the seasonal accumulation pattern of different loline alkaloid concentrations in leaf and stem varied. In most lines, stem loline concentration peaked sharply in late spring and declined during early summer and autumn. The seasonal pattern of leaf loline alkaloid concentration followed the stem concentration except for a sharp decline in early summer followed by an increase in late summer. In most instances, the concentration of N-formyl loline was the highest > N-acetyl loline > N-acetyl norloline > N-methyl loline. The possible role of stem and leaf loline alkaloids to deter pasture-feeding insects is briefly discussed.

scholarly journals Functional response of Harmonia axyridis preying on Acyrthosiphon pisum nymphs: the effect of temperature

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yasir Islam ◽  
Farhan Mahmood Shah ◽  
Xu Rubing ◽  
Muhammad Razaq ◽  
Miao Yabo ◽  
...  
Keyword(s):  
Functional Response ◽  
High Performance ◽  
Acyrthosiphon Pisum ◽  
Harmonia Axyridis ◽  
Effect Of Temperature ◽  
Functional Responses ◽  
Aphid Control ◽  
Host Aphid ◽  
Predator Foraging

AbstractIn the current study, we investigated the functional response of Harmonia axyridis adults and larvae foraging on Acyrthosiphon pisum nymphs at temperatures between 15 and 35 °C. Logistic regression and Roger’s random predator models were employed to determine the type and parameters of the functional response. Harmonia axyridis larvae and adults exhibited Type II functional responses to A. pisum, and warming increased both the predation activity and host aphid control mortality. Female and 4th instar H. axyridis consumed the most aphids. For fourth instar larvae and female H. axyridis adults, the successful attack rates were 0.23 ± 0.014 h−1 and 0.25 ± 0.015 h−1; the handling times were 0.13 ± 0.005 h and 0.16 ± 0.004 h; and the estimated maximum predation rates were 181.28 ± 14.54 and 153.85 ± 4.06, respectively. These findings accentuate the high performance of 4th instar and female H. axyridis and the role of temperature in their efficiency. Further, we discussed such temperature-driven shifts in predation and prey mortality concerning prey-predator foraging interactions towards biological control.

Seasonal changes of SP and NKA in frontal cortex, striatum and testes in the rat. Role of maternal pineal gland

Peptides ◽  
2004 ◽  
Vol 25 (6) ◽  
pp. 997-1004 ◽  
Author(s):  
N Vázquez Moreno ◽  
L Debeljuk ◽  
E Dı́az Rodrı́guez ◽  
C Fernández Alvarez ◽  
B Dı́az López
Keyword(s):  
Pineal Gland ◽  
Frontal Cortex ◽  
Seasonal Changes

Lipid accumulation by migrating monarch butterflies (Danaus plexippus L.)

1993 ◽  
Vol 71 (1) ◽  
pp. 76-82 ◽  
Author(s):  
David L. Gibo ◽  
Jody A. McCurdy
Keyword(s):  
Lipid Accumulation ◽  
Seasonal Changes ◽  
Late Phase ◽  
Danaus Plexippus ◽  
Late Summer ◽  
Dry Mass ◽  
Middle Phase ◽  
Southern Ontario ◽  
Lipid Mass ◽  
Peak Abundance

The migration of Danaus plexippus during the late summer in southern Ontario in 1986 lasted for about 8 weeks and consisted of three phases, an early phase characterized by increasing abundance, a middle phase of peak abundance, and a late phase characterized by declining abundance. As the season progressed, systematic changes were observed in wet mass, dry mass, lean dry mass, lipid mass, and forewing length. Wet mass, lean dry mass, and forewing length were similar for early- and middle-phase individuals, but declined in late-phase migrants. Lipid mass peaked in the middle phase of the migration and then declined abruptly in the late phase. Dry mass also peaked in the middle phase, reflecting changes in lipid mass and lean dry mass. We hypothesize that the observed changes in lipid mass and lean dry mass over the 8 weeks resulted from changes in population structure as well as seasonal changes in the weather, and in availability of nectar. Opposing conclusions reached in previous studies of lipid accumulation in D. plexippus are probably the result of failure to control for phase of migration.

STUDIES ON THE ARTHROPOD FAUNA OF ALFALFA: II. ARTHROPOD–FUNGUS ASSOCIATIONS

1972 ◽  
Vol 104 (9) ◽  
pp. 1405-1412
Author(s):  
A. G. Wheeler
Keyword(s):  
Seasonal Changes ◽  
Immature Stages ◽  
Arthropod Species ◽  
Late Fall ◽  
Medicago Saliva ◽  
Arthropod Fauna

AbstractObservations were made during 1967 to 1969 at Ithaca, N.Y., supplemented by collections at New Cumberland and Carlisle, Pa., on arthropods associated with fungi occurring on alfalfa, Medicago saliva L. Five species of Coleoptera, two species of Diptera, one species each of Collembola and Psocoptera, and nine species of Acari were reared or collected consistently from fungus-covered alfalfa leaves, stems, and seed pods. Attraction to fungi on the plants, principally Alternaria sp., accounted for the presence on alfalfa of arthropod species that normally might be considered as accidentals or visitors. The mycetophagous species thus contributed to the richness of the alfalfa fauna. Immature stages of several species were collected only in late fall or on 3- or 4-year-old plants. The possible role of the fungus-feeding species in seasonal changes in the alfalfa fauna and changes in the fauna in successive years is discussed.

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