Uticaj temperature i kvaliteta hrane na varijabilnost komponenti adaptivne vrednosti i fiziologiju varenja larvi gubara Lymantria dispar L.
Effect of temperature and food quality on variability of fitness components and physiology of digestion in the gypsy moth larvae Lymantria dispar L.
2012
Authors:
Janković Tomanić, MilenaContributors
Stojković, BiljanaLazarević, Jelica
Stojković, Biljana
Šešlija-Jovanović, Darka
Document Type:
Doctoral thesis (Published version)
Metadata
Show full item recordAbstract:
Temperature and food quality affect the performance of gypsy moth larvae
Lymantria dispar L. independently or in an interaction with each other. Survival
strategies of gypsy moth larvae in temperature and nutritionally heterogeneous
environments include various types of reversible and irreversible phenotypic
plasticity, which due to the effect of uptake and distribution of resources affect the
life-history traits and resistance to extreme environmental conditions.
In order to investigate the direct and interactive effects of temperature and
food quality on fitness components, as well as the expression of genetic variation,
gypsy moth larvae were exposed to three different temperatures (suboptimal,
optimal and supraoptimal) and 4 sets of nutrient composition of the diet, which
differed in protein and carbohydrate content. Under the same experimental
conditions, the role of digestion and digestive enzyme activity in adjusting nutrient
quantity and ratio with organism needs at different temperatures was
investigated. Also, it was investigated the effect of nutritional value of the food on
sensitivity of gypsy moth larvae to stressful temperatures.
An adverse temperature and low protein content in food, as well as an
imbalance of protein compared to carbohydrates, reduced performance of gypsy
moth larvae. Effects of temperature and food quality on fitness components -
survival, developmental time, larval weight and relative growth rate were mainly
independent. It has been shown that elevated temperature reduces survival and
duration of development, but leads to an increase of the relative growth rate.
Nutritional composition of food had no effect on survival, but the low protein
content led to prolonged developmental time, reduced larval weight and relative
growth rate of gypsy moth larvae. The relative growth rate of larvae was lower if
carbohydrate content in food was high, while larval weight reduction was greater
if protein content was low and the carbohydrate content was high.
Diet with high protein content led to the decrease in specific activities of total
protease and trypsin, while low protein and high carbohydrate diet decreased
specific activities of carbohydrases, α-amylase and α-glucosidase of larvae.
Temperature and food independently influenced activity of elastase and trypsin, α-
glucosidase and acid phosphatase, while total protease, leucine aminopeptidase,
lipase and alkaline phosphatase activities were significantly affected by interaction
of food and temperature. Change of total protease activity with increasing
temperature consisted in its increased activity on nutritionally poorest and
reduced activity in the richest food, whereas the changes of α-amylase activity in
response to increasing temperatures consisted in increased activities in low
carbohydrates food conditions. Responses of lipase and acid phosphatase to low
protein and high carbohydrate content in food, i.e. nutritionally poor food, were an
increase in their activities, while alkaline phosphatase activity increased with
increasing temperature on food that are low in both protein and carbohydrate
content.
In response to temperature, “reverse pattern" of activity was demonstrated
between the endo and exopeptidase (elastase and leucine aminopeptidase), endo
and exocarbohydrase (α-amylase and α-glucosidase) and among alkaline and acid
phosphatases, as well as changes in phenotypic correlations between certain
classes of digestive enzymes to adverse temperatures and suboptimal nutritional
content of food.
The effects of temperature and food quality were also noticeable at the level of
expression of the genetic variability of developmental time, as well as by
significant variability of phenotypic plasticity in response to temperature. At the
optimal temperature there was an increase of heritability of larval weight on
nutritionally poorest food, while rise in temperature decreased heritability of
larval weight if the food was low in one or both nutrients. Within environments
genetic correlations for developmental time and larval weight in adverse
environmental conditions are negative, i.e. larvae, which were characterized by
longer larval development had lower larval weight but, in optimal conditions did
not reveal any significant correlation between these traits. Majority of the acrossenvironment
genetic correlations both for developmental time and larval weight
were positive, which was an expected result for generalist species. Acrossenvironments
genetic correlations for developmental time were positive and not
significantly different from “one”, which represented a constraint for the evolution
of optimal phenotypic plasticity. Across-environments genetic correlations for
larval weight were positive and significantly different from “1” and although, for
larval weight was not found variability of phenotypic plasticity, evolution of
plasticity was possible due to the significant difference in heritability between
environments.
The larvae of gypsy moth ”can benefit” from adverse conditions of nutritionally
poor food, because the gypsy moth resistance to temperature stress, which was
estimated based on survival time, showed the highest value particularly in such
conditions. In contrast, the limiting factor for survival was the previous acclimation
to (constant) elevated temperature during early larval stages and high content of
protein and carbohydrates in food. Suboptimal temperature and food with the
lowest ratio of proteins compared to carbohydrates, as well as an increase in
temperature on nutrient-poorest food, significantly reduced the ability of gypsy
moth larvae to molt in stressful temperatures.
Keywords:
Lymantria dispar L.; Temperature; Food quality; Life-history traits; Phenotipic plasticity; Digestive enzymes specific activities; ResistanceSource:
University of Belgrade, Faculty of Biology, 2012, 1-231Funding / projects:
- Fiziološki i evolucioni aspekti stresnog odgovora u prirodnim i laboratorijskim populacijama (RS-143033)
- The effects of magnetic fields and other environmental stressors on the physiological responses and behavior of different species (RS-MESTD-Basic Research (BR or ON)-173027)
URI
http://eteze.bg.ac.rs/application/showtheses?thesesId=416https://fedorabg.bg.ac.rs/fedora/get/o:6140/bdef:Content/download
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http://nardus.mpn.gov.rs/123456789/2094
https://radar.ibiss.bg.ac.rs/handle/123456789/2389