Fall condition factor and temperature influence the incidence of metamorphosis in sea lampreys, Petromyzon marinus

1994 ◽  
Vol 72 (6) ◽  
pp. 1134-1140 ◽  
Author(s):  
John A. Holmes ◽  
John H. Youson

Larval sea lampreys of immediate premetamorphic size (at least 120 mm and 3.0 g) were subjected to ambient or constant 21 °C temperature regimes for 9 months to investigate the influence of temperature and a fall condition factor (CF) of 1.50 or greater on the incidence of metamorphosis the following summer. The incidence of metamorphosis was 53% in the ambient temperature regime (29/55) and only 2% (1/55) in the constant temperature regime. About 64% (7/11) of the presumptively metamorphic larvae in the ambient temperature regime entered metamorphosis compared with 10% (1/10) in the constant temperature regime. Our predictions of metamorphosis based on CF were consistent with the observation that seven presumptively metamorphic larvae (CF ≥ 1.50) metamorphosed in the ambient temperature regime and that there was no metamorphosis among presumptively nonmetamorphic larvae in the constant temperature regime. Significantly more presumptively nonmetamorphic larvae in the ambient regime entered metamorphosis and fewer presumptively metamorphic larvae (CF < 1.50) metamorphosed in the constant temperature regime than expected. We attribute this response to the effects of temperature on metabolic processes. Larval sea lampreys of the appropriate size (≥ 120 mm and ≥ 3.0 g) with a CF of 1.50 or greater in the fall will usually enter metamorphosis the following July, but the accuracy of these predictions may be improved in some populations by using an empirically determined CF criterion that reflects seasonal or population differences in mass–length relationships.

1994 ◽  
Vol 51 (9) ◽  
pp. 2045-2051 ◽  
Author(s):  
J. A. Holmes ◽  
F. W. H. Beamish ◽  
J. G. Seelye ◽  
S. A. Sower ◽  
J. H. Youson

After 11 mo in the laboratory, significantly more sea lamprey, Petromyzon marinus, larvae from the Chippewa River, Michigan, metamorphosed in an ambient temperature regime (3 ± 2 animals∙tank−1) compared with a fixed 21 °C temperature (0 animals); photoperiod and food deprivation did not have detectable effects on the incidence of metamorphosis. Metamorphosing animals in our laboratory study were significantly smaller in size (length and weight) and had a lower condition factor (CF) than animals from the same population that metamorphosed a year earlier under field and shorter term laboratory conditions. We also predicted, using criteria of 120 mm, 3.0 g, and a CF of 1.50, that 12 and 14% of the animals in the ambient and fixed temperature regimes, respectively, would metamorphose. Our prediction for the ambient temperature did not differ significantly from observed (11%). We suggest that larvae in landlocked populations of sea lamprey that are at least 120 mm long, weigh 3.0 g, and have a CF of 1.50 or greater in the fall can be predicted to metamorphose the following summer. Furthermore, our data show that low temperature during the winter followed by rising temperature in the spring is the primary environmental cue initiating metamorphosis in sea lamprey.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Uros Glavinic ◽  
Jasmin Varga ◽  
Anca Ioana Paslaru ◽  
Jeannine Hauri ◽  
Paul Torgerson ◽  
...  

Abstract Background Since the huge epidemic of Zika virus (ZIKV) in Brazil in 2015, questions were raised to understand which mosquito species could transmit the virus. Aedes aegypti has been described as the main vector. However, other Aedes species (e.g. Ae. albopictus and Ae. japonicus) proven to be competent for other flaviviruses (e.g. West Nile, dengue and yellow fever), have been described as potential vectors for ZIKV under laboratory conditions. One of these, the Asian bush mosquito, Ae. japonicus, is widely distributed with high abundances in central-western Europe. In the present study, infection, dissemination and transmission rates of ZIKV (Dak84 strain) in two populations of Ae. japonicus from Switzerland (Zürich) and France (Steinbach, Haut-Rhin) were investigated under constant (27 °C) and fluctuating (14–27 °C, mean 23 °C) temperature regimes. Results The two populations were each able to transmit ZIKV under both temperature regimes. Infectious virus particles were detected in the saliva of females from both populations, regardless of the incubation temperature regime, from 7 days post-exposure to infectious rabbit blood. The highest amount of plaque forming units (PFU) (400/ml) were recorded 14 days post-oral infection in the Swiss population incubated at a constant temperature. No difference in terms of infection, dissemination and transmission rate were found between mosquito populations. Temperature had no effect on infection rate but the fluctuating temperature regime resulted in higher dissemination rates compared to constant temperature, regardless of the population. Finally, transmission efficiency ranged between 7–23% and 7–10% for the constant temperature and 0–10% and 3–27% under fluctuating temperatures for the Swiss and the French populations, respectively. Conclusions To the best of our knowledge, this is the first study confirming vector competence for ZIKV of Ae. japonicus originating from Switzerland and France at realistic summer temperatures under laboratory conditions. Considering the continuous spread of this species in the northern part of Europe and its adaptation at cooler temperatures, preventative control measures should be adopted to prevent possible ZIKV epidemics.


2020 ◽  
Author(s):  
Uros Glavinic ◽  
Jasmin Varga ◽  
Anca Iona Paslaru ◽  
Jeannine Hauri ◽  
Paul Torgerson ◽  
...  

Abstract Background Since the huge epidemic of Zika virus (ZIKV) in Brazil in 2015, questions were raised to understand which mosquito species could transmit the virus. Aedes aegypti has been described as the main vector. However, other Aedes species (e.g. Ae. albopictus and Ae. japonicus) proven to be competent for other Flaviviruses (e.g.West Nile, dengue and yellow fever), have been described as potential vector for ZIKV under laboratory conditions. To name one, the Asian bush mosquito Ae. japonicus which is widely distributed with high abundances in Central-Western Europe. In the present study, infection, dissemination and transmission rates of ZIKV (Dak84 strain) in two populations of Ae. japonicus from Switzerland (Zürich) and France (Steinbach, Haut-Rhin) were investigated under constant (27 °C) and fluctuating (14-27 °C, mean 23 °C) temperature regimes.Results The two populations were each able to transmit ZIKV under both temperature regimes. Infectious virus particles were detected in the saliva of females from both populations, regardless of the incubation temperature regime, from 7 days post exposure to infectious rabbit blood. The highest amount of Plaque Forming Unit (PFU) (400/ml) were recorded 14 days post oral infection in the Swiss population incubated at constant temperature. No difference in term of infection, dissemination and transmission rate were found between mosquito populations.Temperature had no effect on infection rate but the fluctuating temperature regime resulted in higher dissemination rates comparing to constant temperature, regardless of the population. Finally, transmission efficiency ranged between 7-23% and 7-10% for the constant temperature and 0-10% and 3-27% under fluctuating temperatures for the Swiss and the French populations, respectively.Conclusions This is the first work confirming vector competence for ZIKV of Ae. japonicus originating from Switzerland and France at realistic summer temperatures under laboratory conditions. Considering the continuous spread of this species in the northern part of Europe and its adaptation at cooler temperatures, preventative control measures should be adopted to prevent possible ZIKV epidemics.


1975 ◽  
Vol 15 (76) ◽  
pp. 705 ◽  
Author(s):  
MJ Barbetti

Aspects of the development and progression of blackleg crown canker in rape seedlings (Brassica napus and B. campestris), following stem infection by L. maculans ascospores were examined at three temperature regimes; 12/7�C, 18/11�C, and 24/15�C. Crown cankers were produced at all temperatures on seedlings inoculated one week after germination. Temperature regime was shown to be a major factor determining the time of first appearance of crown cankers after inoculation; 12/7�C being the least favourable for crown canker development of the three regimes used. Temperature regime had a significant effect upon the time taken for infected plants to die, the 12/7�C regime being the optimum for slowest plant death, Infected B. napus plants died at a faster rate than B. campestris. Temperature regime was also shown to influence the nature, or type, of crown canker that developed.


2016 ◽  
Vol 96 (3) ◽  
pp. 321-328
Author(s):  
Michael E. Foley

Germinability of dormant seeds or the capacity to germinate under particular conditions is sometimes enhanced by a diurnal alternating temperature regime relative to a constant temperature. Alternating temperature regimes vary in amplitude (difference between the minimum and maximum) and midpoint (average). The aim of this research was to test the effects of amplitude and midpoint regimes on germination of dormant leafy spurge seed from a Fargo, ND population in water and gibberellic acid (GA3). The optimal regimes for germination in both water and GA3 were 20:30 °C (16 h:8 h) and 20:35 °C (19 h:5 h), which provided amplitudes of 10 °C and 15 °C, respectively, with both conditions having a midpoint temperature of 23.3 °C. However, midpoint temperature of 22 °C to 27 °C were equally effective for germination under the 20:30 °C and 20:35 °C alternating temperature regimes. Additional alternating temperature regimes with amplitudes of 15 °C (15:30 °C and 10:25 °C), 20 °C (10:30 °C), and 25 °C (10:35 °C) generally displayed reduced germination in both water and GA3, which is likely attributable to the low initial alternating temperature (≤15 °C) component of the regime relative to the higher initial temperature of 20 °C for the optimum regimes of 20:30 °C and 20:35 °C. Under the alternating temperature regimes tested, seeds germinated in GA3 generally displayed higher germination (≥80%) compared with seeds in water (30%–50%).


1980 ◽  
Vol 37 (11) ◽  
pp. 1827-1834 ◽  
Author(s):  
H. A. Purvis

Sea lamprey (Petromyzon marinus) ammocoetes of known age were confined in three locations to determine the effects of temperature on the incidence of metamorphosis. Sixty ammocoetes were held in each of Lake Superior, the Big Garlic River, and in an aquarium at room temperature for each of 4 yr. The highest incidence of metamorphosis (75–100%) occurred at 20–21 °C (aquarium), an intermediate rate (46–76%) at 14–16 °C (Big Garlic River), and the lowest (5–10%) at 7–11 °C (Lake Superior). Density appeared to be the dominant factor in regulating the length of larval and transformed sea lampreys. Mean lengths of larval and transformed sea lampreys increased markedly after stream treatments with selective lampricides. Prediction of lengths at which metamorphosis occurs in re-established populations of sea lampreys is uncertain because of variability in growth rates. Initial metamorphosis in a year-class is dependent on growth rates of ammocoetes. Because of wide variation in growth rates, metamorphosis may begin at age III among fast-growing populations and not until age VII among slow-growing populations.Key words: Petromyzon marinus, sea lamprey; metamorphosis, age, length, Great Lakes


1973 ◽  
Vol 21 (2) ◽  
pp. 102-109 ◽  
Author(s):  
K. Verkerk ◽  
C.J.T. Spitters

In the first of 2 experiments lettuces were grown either under natural light conditions in the glasshouse in December and January or under 8- or 16-h daylengths, with several temperature regimes, and the leaf area per plant was measured after 22 and 45 days. Under natural light growth during the first 22 days was slight but subsequent growth was greatest with a light/dark temperature regime of 13/13 deg C, followed by one of 17/17 deg . With an 8-h day growth with diurnally changing temperatures was much greater than with constant ones, the best results being obtained with a regime of 25/17 deg . With a 16-h day the effect of diurnal temperature was much less marked and a constant high temperature regime of 21/21 deg gave better results than one of 25/17 deg . In the second experiment the plants were grown for 4 weeks under the same temperature regimes with 8- or 16-h daylengths, but the light intensity was varied by placing the plants at 2 vertical distances from the overhead lamps and all plants receiving a 16-h daylength were shaded by cheesecloth. The best results were obtained with a 16-h daylength with the plants placed close to the lamps; the effects of temperature were not so marked, but regimes of 25/17, 21/13 or 17/17 deg were the most satisfactory. (Abstract retrieved from CAB Abstracts by CABI’s permission)


2020 ◽  
Author(s):  
Uros Glavinic ◽  
Jasmin Varga ◽  
Anca Iona Paslaru ◽  
Jeannine Hauri ◽  
Paul Torgerson ◽  
...  

Abstract Background Since the huge epidemic of Zika virus (ZIKV) in Brazil in 2015, questions were raised to understand which mosquito species could transmit the virus. Aedes aegypti has been described as the main vector. However, other Aedes species (e.g. Ae. albopictus and Ae. japonicus) proven to be competent for other Flaviviruses (e.g.West Nile, dengue and yellow fever), have been described as potential vector for ZIKV under laboratory conditions. One of these, the Asian bush mosquito Ae. japonicus is widely distributed with high abundances in Central-Western Europe. In the present study, infection, dissemination and transmission rates of ZIKV (Dak84 strain) in two populations of Ae. japonicus from Switzerland (Zürich) and France (Steinbach, Haut-Rhin) were investigated under constant (27 °C) and fluctuating (14-27 °C, mean 23 °C) temperature regimes.Results The two populations were each able to transmit ZIKV under both temperature regimes. Infectious virus particles were detected in the saliva of females from both populations, regardless of the incubation temperature regime, from 7 days post exposure to infectious rabbit blood. The highest amount of Plaque Forming Unit (PFU) (400/ml) were recorded 14 days post oral infection in the Swiss population incubated at constant temperature. No difference in terms of infection, dissemination and transmission rate were found between mosquito populations.Temperature had no effect on infection rate but the fluctuating temperature regime resulted in higher dissemination rates compared to constant temperature, regardless of the population. Finally, transmission efficiency ranged between 7-23% and 7-10% for the constant temperature and 0-10% and 3-27% under fluctuating temperatures for the Swiss and the French populations, respectively.Conclusions This is the first work confirming vector competence for ZIKV of Ae. japonicus originating from Switzerland and France at realistic summer temperatures under laboratory conditions. Considering the continuous spread of this species in the northern part of Europe and its adaptation at cooler temperatures, preventative control measures should be adopted to prevent possible ZIKV epidemics.


2020 ◽  
Author(s):  
Uros Glavinic ◽  
Jasmin Varga ◽  
Anca Ioana Paslaru ◽  
Jeannine Hauri ◽  
Paul Torgerson ◽  
...  

Abstract Background: Since the huge epidemic of Zika virus (ZIKV) in Brazil in 2015, questions were raised to understand which mosquito species could transmit the virus. Aedes aegypti has been described as the main vector. However, other Aedes species (e.g. Ae. albopictus and Ae. japonicus) proven to be competent for other flaviviruses (e.g. West Nile, dengue and yellow fever), have been described as potential vectors for ZIKV under laboratory conditions. One of these, the Asian bush mosquito, Ae. japonicus, is widely distributed with high abundances in central-western Europe. In the present study, infection, dissemination and transmission rates of ZIKV (Dak84 strain) in two populations of Ae. japonicus from Switzerland (Zürich) and France (Steinbach, Haut-Rhin) were investigated under constant (27 °C) and fluctuating (14–27 °C, mean 23 °C) temperature regimes.Results: The two populations were each able to transmit ZIKV under both temperature regimes. Infectious virus particles were detected in the saliva of females from both populations, regardless of the incubation temperature regime, from 7 days post-exposure to infectious rabbit blood. The highest amount of plaque forming units (PFU) (400/ml) were recorded 14 days post-oral infection in the Swiss population incubated at a constant temperature. No difference in terms of infection, dissemination and transmission rate were found between mosquito populations.Temperature had no effect on infection rate but the fluctuating temperature regime resulted in higher dissemination rates compared to constant temperature, regardless of the population. Finally, transmission efficiency ranged between 7–23% and 7–10% for the constant temperature and 0–10% and 3–27% under fluctuating temperatures for the Swiss and the French populations, respectively.Conclusions: To the best of our knowledge, this is the first study confirming vector competence for ZIKV of Ae. japonicus originating from Switzerland and France at realistic summer temperatures under laboratory conditions. Considering the continuous spread of this species in the northern part of Europe and its adaptation at cooler temperatures, preventative control measures should be adopted to prevent possible ZIKV epidemics.


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