Environmental control of univoltinism and its evolution in an insect species

1976 ◽  
Vol 54 (2) ◽  
pp. 260-265 ◽  
Author(s):  
Maurice J. Tauber ◽  
Catherine A. Tauber
Keyword(s):  
Environmental Control ◽  
Natural Populations ◽  
Adult Emergence ◽  
Early Spring ◽  
Insect Species ◽  
Major Barrier ◽  
K Value ◽  
Short Day ◽  
Actual Duration ◽  
Diapause Development

Chrysopa downesi, a conifer-inhabiting unicyclic insect species, shares many features in its seasonal cycle with some well-studied single-brooded birds: a quantitative response to winter daylengths, reproduction in early spring, a summer 'photorefractory' phase, and a short-day requirement for termination of this phase. Under natural conditions, C. downesi has an aestival–autumnal–hibernal reproductive diapause that is primarily controlled by photoperiod. The short-day requirement for diapause termination is fulfilled in October. Subsequently, during winter, the rate of diapause development is directly related to the actual duration of daylength, and diapause ends between March 1 and March 21. Oviposition begins in mid-April. The rate of egg and larval development is primarily regulated by temperature; the lower thermal threshold for development (t) is 11 °C, and K value (heat-degree days) for the period from egg to adult emergence is 378 day °C.The late ending of C. downesi's diapause, its relatively high t value, and its aestival diapause separate temporally the reproductive periods of this species and its sympatric sibling species, Chrysopa carnea. The asynchronous seasonal cycles of C. downesi and C. carnea form a major barrier to hybridization between natural populations of the two species in the northeastern United States.

Diapause and overwintering of the carrot fly, Psila rosae (F.) (Diptera: Psilidae)

1981 ◽  
Vol 71 (4) ◽  
pp. 583-590 ◽  
Author(s):  
A. J. Burn ◽  
T. H. Coaker
Keyword(s):  
Adult Emergence ◽  
Early Spring ◽  
Pupal Weight ◽  
Prepupal Stage ◽  
Psila Rosae ◽  
Carrot Fly ◽  
Soil Temperatures ◽  
Similar Temperature ◽  
Effects Of Temperature ◽  
Diapause Development

AbstractPsila rosae (F.) overwinters in Britain in both the larval and pupal stages. Overwintering pupae formed in October and November at soil temperatures of between 10 and 16°C entered diapause. A period of similar temperature in the laboratory during the prepupal stage also caused pupae to enter diapause. Overwintering larvae continued to feed and gain weight; they pupated in early spring at soil temperatures of 2–8°C but did not enter diapause. The sensitivity to diapause-inducing conditions decreased between November and March, associated with changes in developmental temperatures and pupal weight. The differential effects of temperature on larval, pupal and diapause development together serve to synchronise adult emergence from the overwintering population. The mechanisms which allow overwintering by a variable proportion of larvae and pupae also provide the opportunity for the development of a third generation of adult flies in October and November.

scholarly journals Spring emergence of Canadian Delia radicum and synchronization with its natural enemy, Aleochara bilineata

2010 ◽  
Vol 142 (3) ◽  
pp. 234-249 ◽  
Author(s):  
L.D. Andreassen ◽  
U. Kuhlmann ◽  
J.W. Whistlecraft ◽  
J.J. Soroka ◽  
P.G. Mason ◽  
...  
Keyword(s):  
Adult Emergence ◽  
Development Rate ◽  
Delia Radicum ◽  
Aleochara Bilineata ◽  
Development Rates ◽  
Models Of Development ◽  
Soil Temperatures ◽  
Truncated Normal ◽  
Diapause Development ◽  
Spring Emergence

AbstractTo characterize time of spring emergence following post-diapause development, Delia radicum (L.) (Diptera: Anthomyiidae) from Saskatchewan, Manitoba, and southwestern Ontario were collected in fall, maintained over winter at 1 °C, then transferred to higher constant temperatures until adult emergence. At each location there were “early” and “late” phenotypes. Truncated normal models of temperature dependency of development rate were fitted for each phenotype from each location. We provide the first evidence of geographic variation in the criteria separating these phenotypes. Separation criteria and models for early and late phenotypes at the two prairie locations, approximately 700 km apart, were indistinguishable, but differed from those for Ontario. Prairie phenotypes developed more slowly than Ontario phenotypes, and more prairie individuals were of the late phenotype. Poor synchronization of spring emergence could impair predation of D. radicum eggs by adult Aleochara bilineata Gyllenhal (Coleoptera: Staphylinidae). Aleochara bilineata from Manitoba were reared and development rates modelled as for D. radicum. Models of development rates for the two species, when combined with simulated soil temperatures for two prairie locations, suggest that emergence of adult A. bilineata is well synchronized with availability of D. radicum eggs in prairie canola.

scholarly journals A rapidly evolved shift in life history timing during ecological speciation is driven by the transition between developmental phases

2020 ◽  
Author(s):  
Thomas H. Q. Powell ◽  
Andrew Nguyen ◽  
Qinwen Xia ◽  
Jeffrey L. Feder ◽  
Gregory J. Ragland ◽  
...  
Keyword(s):  
Developmental Trajectories ◽  
Maintenance Phase ◽  
Adult Emergence ◽  
Physiological Basis ◽  
Data Accessibility ◽  
Seasonal Timing ◽  
Pupal Diapause ◽  
Phases Of Development ◽  
Diapause Development ◽  
Developmental Phases

AbstractFor insect species in temperate environments, seasonal timing is often governed by the regulation of diapause, a complex developmental program that allows insects to weather unfavorable conditions and synchronize their lifecycles with available resources. Diapause consists of a series of phases that govern initiation, maintenance, and termination of this developmental pathway. The evolution of insect seasonal timing depends in part on how these phases of diapause development and post-diapause development interact to affect variation in phenology. Here, we dissect the physiological basis of a recently evolved phenological shift in Rhagoletis pomonella (Diptera: Tephritidae), a model system for ecological divergence. A recently derived population of R. pomonella shifted from specializing on native hawthorn fruit to earlier fruiting introduced apples, resulting in a 3-4 week shift in adult emergence timing. We tracked metabolic rates of individual flies across post-winter development to test which phases of development may act either independently or in combination to contribute to this recently evolved divergence in timing. Apple and hawthorn flies differed in a number of facets of their post-winter developmental trajectories. However, divergent adaptation in adult emergence phenology in these flies was due almost entirely to the end of the pupal diapause maintenance phase, with post-diapause development having a very small effect. The relatively simple underpinnings of variation in adult emergence phenology suggest that further adaptation to seasonal change in these flies for this trait might be largely due to the timing of diapause termination unhindered by strong covariance among different components of post-diapause development.Data accessibilityAll data (in the form of tables of all metabolic rate measurements for all individual flies in the study) will be available on DRYAD when the manuscript is published.

scholarly journals Assessment of the susceptibility status of Aedes aegypti (Diptera: Culicidae) populations to pyriproxyfen and malathion in a nation-wide monitoring of insecticide resistance performed in Brazil from 2017 to 2018

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Kauara Brito Campos ◽  
Ademir Jesus Martins ◽  
Cynara de Melo Rodovalho ◽  
Diogo Fernandes Bellinato ◽  
Luciana dos Santos Dias ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Mosquito Control ◽  
Natural Populations ◽  
Adult Emergence ◽  
World Health ◽  
Two Generations ◽  
Wide Scale ◽  
Susceptibility Tests ◽  
The One ◽  
Health Organization

Abstract Background Chemical mosquito control using malathion has been applied in Brazil since 1985. To obtain chemical control effectiveness, vector susceptibility insecticide monitoring is required. This study aimed to describe bioassay standardizations and determine the susceptibility profile of Ae. aegypti populations to malathion and pyriproxyfen, used on a national scale in Brazil between 2017 and 2018, and discuss the observed impacts in arbovirus control. Methods The diagnostic-doses (DD) of pyriproxyfen and malathion were determined as the double of adult emergence inhibition (EI) and lethal doses for 99% of the Rockefeller reference strain, respectively. To monitor natural populations, sampling was performed in 132 Brazilian cities, using egg traps. Colonies were raised in the laboratory for one or two generations (F1 or F2) and submitted to susceptibility tests, where larvae were exposed to the pyriproxyfen DD (0.03 µg/l) and adults, to the malathion DD determined in the present study (20 µg), in addition to the one established by the World Health Organization (WHO) DD (50 µg) in a bottle assay. Dose-response (DR) bioassays with pyriproxyfen were performed on populations that did not achieve 98% EI in the DD assays. Results Susceptibility alterations to pyriproxyfen were recorded in six (4.5%) Ae. aegypti populations from the states of Bahia and Ceará, with Resistance Ratios (RR95) ranging from 1.51 to 3.58. Concerning malathion, 73 (55.3%) populations distributed throughout the country were resistant when exposed to the local DD 20 µg/bottle. On the other hand, no population was resistant, and only 10 (7.6%) populations in eight states were considered as exhibiting decreased susceptibility (mortality ratios between 90 and 98%) when exposed to the WHO DD (50 µg/bottle). Conclusions The feasibility of conducting an insecticide resistance monitoring action on a nation-wide scale was confirmed herein, employing standardized and strongly coordinated sampling methods and laboratory bioassays. Brazilian Ae. aegypti populations exhibiting decreased susceptibility to pyriproxyfen were identified. The local DD for malathion was more sensitive than the WHO DD for early decreased susceptibility detection.

Seasonal changes in concentrations of plasma hormones in the male ring dove (Streptopelia risoria)

1986 ◽  
Vol 108 (3) ◽  
pp. 385-391 ◽  
Author(s):  
R. W. Lea ◽  
P. J. Sharp ◽  
H. Klandorf ◽  
S. Harvey ◽  
I. C. Dunn ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Plasma Corticosterone ◽  
Early Spring ◽  
Energy Requirements ◽  
Breeding Cycle ◽  
Plasma Prolactin ◽  
Winter Solstice ◽  
Natural Lighting ◽  
Short Day ◽  
Ring Dove

ABSTRACT Seasonal changes in concentrations of plasma LH, prolactin, thyroxine (T4), GH and corticosterone were measured in captive male ring doves exposed to natural lighting at latitude 56 °N. Plasma LH levels decreased steeply in autumn when the daylength fell below about 12·5 h but increased in November as the birds became short-day refractory. In comparison with plasma LH concentrations in a group of short-day refractory birds exposed to 6 h light/day from the winter solstice, plasma LH levels in birds exposed to natural lighting increased further in spring after the natural daylength reached about 12·5 h. There were no seasonal changes in plasma prolactin concentrations and plasma T4 concentrations were at their highest during December, January and February, the coldest months of the year. The seasonal fall in plasma LH levels in September was associated with a transitory increase in plasma T4, a transitory decrease in plasma corticosterone and a sustained increase in plasma GH. It is suggested that in the ring dove, short-day refractoriness develops rapidly in November to allow the bird to breed when the opportunity arises, during the winter and early spring. The annual breeding cycle is synchronized by a short-day induced regression of the reproductive system in the autumn, the primary function of which may be to enable the birds to meet the energy requirements for the annual moult. The changes in plasma T4, corticosterone and especially of GH at this time of year are probably concerned with the control of moult or the associated changes in energy requirements. J. Endocr. (1986) 108, 385–391

The epidemiology of Nematodirus battus – is it changing?

Parasitology ◽  
1991 ◽  
Vol 102 (1) ◽  
pp. 147-155 ◽  
Author(s):  
D. Rh. Thomas
Keyword(s):  
Life History ◽  
Natural Populations ◽  
Early Spring ◽  
Late Spring ◽  
North Wales ◽  
Site Variation ◽  
Experimental Plots

SUMMARYNatural populations of 3rd-stage Nematodirus battus larvae were present on pastures in North Wales throughout the year; highest numbers were present in late spring, with smaller peaks occurring in autumn. Inter-site variation was observed in the timing and magnitude of these peaks. Hatching on experimental plots occurred 2 months to 2 years following deposition of eggs. Intraspecific and inter-site variation occurred in the timing, and inter-site variation occurred in the magnitude, of the mass hatch on upland and lowland experimental plots. Arrested 4th-stage N. battus were recovered from Welsh Mountain lambs. Percentage arrest and number of arrested worms was greatest during winter and early spring. The prevalence and intensity of N. battus infection in 1-, 2- and 3-year-old Welsh Mountain ewes was low. The plasticity exhibited in the parasite's life-history is discussed in relation to potential changes in the epidemiology of nematodiriasis.

scholarly journals Detection of Geosmithia morbida on Numerous Insect Species in Four Eastern States

2019 ◽  
Vol 20 (3) ◽  
pp. 133-139 ◽  
Author(s):  
Melanie Moore ◽  
Jennifer Juzwik ◽  
Fredric Miller ◽  
Leah Roberts ◽  
Matthew D. Ginzel
Keyword(s):  
Bark Beetles ◽  
Adult Emergence ◽  
Juglans Nigra ◽  
Insect Species ◽  
Geosmithia Morbida ◽  
Pityophthorus Juglandis ◽  
Thousand Cankers Disease ◽  
Branch Dieback ◽  
Walnut Twig Beetle ◽  
Β Tubulin

Thousand cankers disease is caused by the coalescence of numerous Geosmithia morbida cankers on branches and stems of Juglans species, leading to branch dieback and eventual tree death. The fungus sporulates in galleries of the walnut twig beetle (Pityophthorus juglandis), allowing for acquisition of pathogen propagules and its subsequent transmission to other branches or trees following adult emergence. Recently, G. morbida has been isolated from Xylosandrus crassiusculus and Xyleborinus saxesenii collected in Ohio and Stenomimus pallidus collected in Indiana. These beetles are known to colonize diseased Juglans nigra in these states. In this study, an operational trap survey for ambrosia beetles, bark beetles, and other weevils was conducted in four eastern states, and captured beetles were assayed to detect G. morbida using both culture and PCR-based methods. A new primer pair (GmF3/GmR13), based on the β-tubulin region, was designed for G. morbida DNA detection. The pathogen was detected on 18 insect species using molecular methods, and live cultures were isolated from two species. This is the first report of the pathogen in Illinois and Minnesota.

scholarly journals Infanticide by females is a leading source of juvenile mortality in a large social carnivore

2020 ◽  
Author(s):  
Ally K Brown ◽  
Malit O Pioon ◽  
Kay E Holekamp ◽  
Eli D Strauss
Keyword(s):  
Natural Populations ◽  
The Body ◽  
Spotted Hyena ◽  
Major Barrier ◽  
Juvenile Mortality ◽  
Adult Females ◽  
Social Animals ◽  
Mating Opportunities

AbstractSocial animals benefit from their group-mates, so why do they sometimes kill each other’s offspring? A major barrier to understanding the evolution of infanticide is a lack of data from natural populations. Especially when perpetrated by females, infanticide remains poorly understood, because the increased mating opportunities that explain infanticide by males do not apply in females. Using 30 years of data from several spotted hyena groups, we show that infanticide is a leading source of juvenile mortality, and we describe the circumstances under which it occurs. In all observed cases, killers were adult females, but victims could be of both sexes. Killers only sometimes consumed the victims. Mothers sometimes cared for their deceased offspring, and sometimes consumed the body. Killers tended to be higher-ranking than the mothers of victims, and killers were sometimes aided by kin. Our results are consistent with theory that infanticide by females reflects competition among matrilines.

scholarly journals An olfactory receptor gene underlies reproductive isolation in perfume-collecting orchid bees

2019 ◽  
Author(s):  
P. Brand ◽  
I. A. Hinojosa-Díaz ◽  
R. Ayala ◽  
M. Daigle ◽  
C. L. Yurrita Obiols ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Odorant Receptor ◽  
Receptor Gene ◽  
Rapid Evolution ◽  
Natural Populations ◽  
Reproductive Barriers ◽  
Species Identity ◽  
Orchid Bees ◽  
Major Barrier ◽  
Genetic Mechanisms

Speciation is facilitated by the evolution of reproductive barriers that prevent or reduce hybridization among diverging lineages. However, the genetic mechanisms that control the evolution of reproductive barriers remain elusive, particularly in natural populations. We identify a gene associated with divergence in chemical courtship signaling in a pair of nascent orchid bee lineages. Male orchid bees collect perfume compounds from flowers and other sources to subsequently expose during courtship display, thereby conveying information on species identity. We show that these two lineages exhibit differentiated perfume blends and that this change is associated with the rapid evolution of a single odorant receptor gene. Our study suggests that reproductive isolation evolved through divergence of a major barrier gene involved in chemically mediated pre-mating isolation via genetic coupling.

Sign in / Sign up

Export Citation Format

Share Document