@phdthesis{
author = "Janković Tomanić, Milena",
year = "2012",
abstract = "Temperatura i kvalitet hrane utiču na performansu larvi gubara, Lymantria
dispar L. nezavisno ili u međusobnoj interakciji. Strategije preživljavanja larvi
gubara u temperaturno kao i nutritivno heterogenoj sredini obuhvataju različite
tipove reverzibilne i ireverzibilne fenotipske plastičnosti, koje preko uticaja na
usvajanje i raspodelu resursa utiču na osobine životne istorije i rezistentnost
prema ekstremnim uslovima životne sredine.
U cilju ispitivanja efekata temperature i kvaliteta hrane, tj. sadržaja proteina i
ugljenih hidrata u hrani na komponente adaptivne vrednosti, kao i ekspresiju
genetičke varijabilnosti, larve gubara su izložene delovanju tri različite
temperature (suboptimalna, optimalna i supraoptimalna) i 4 kombinacije
hranljivog sastava dijete, koje su se međusobno razlikovale kako u ukupnom
sadržaju proteina i ugljenih hidrata, tako i u njihovom međusobnom odnosu. U
istim eksperimentalnim uslovima ispitivana je uloga procesa varenja, odnosno
aktivnosti digestivnih enzima u usklađivanju odnosa i količine unetih nutienata sa
potrebama organizma na različitim temperaturama. Takođe, ispitan je uticaj
nutritivne vrednosti i balansiranosti hrane na senzitivnost gubara prema stresnim
temperaturama.
Nepovoljne temperature i nizak sadržaj proteina u hrani, kao i disbalans
proteina u odnosu na ugljene hidrate, smanjuju performansu larvi gubara. Uticaji
temperature i kvaliteta hrane na komponente adaptivne vrednosti: preživljavanje,
trajanje razvića, masu i relativnu brzinu rasta, uglavnom su međusobno nezavisni.
Pokazano je da povišena temperatura smanjuje preživljavanje i trajanje razvića
larvi ali dovodi do povećanja relativne brzine rasta. Nutritivni sastav hrane nije
uticao na preživljavanje, ali je nizak sadržaj proteina u hrani dovodio do
produžavanja razvića, smanjenja mase i relativne brzine rasta larvi. Relativna
brzina rasta larvi je bila manja i pri visokom sadržaju ugljenih hidrata u hrani, dok
je smanjenje mase larvi na hrani sa niskim sadržajem proteina bilo veće ako je i
sadržaj ugljenih hidrata bio nizak.
Ako se larve hrane dijetom sa visokim sadržajem proteina dolazi do smanjenja
aktivnosti proteolitičkih enzima, ukupnih proteaza i tripsina, dok se u uslovima
niskog sadžaja proteina i visokog sadržaja ugljenih hidrata smanjuje aktivnost
karbohidraza, α-amilaze i α-glikozidaze. Temperatura i hrana deluju nezavisno na
aktivnost elastaze i tripsina, α-glikozidaze i kiselih fosfataza, dok je za aktivnost
ukupnih proteaza, leucin aminopeptidaze, α-amilaze, lipaze i alkalne fosfataze
pokazana značajna interakcija temperature i nutritivnog sastava dijete. Promena
aktivnosti ukupnih proteaza sa porastom temperature sastoji se u povećanju
aktivnosti na nutritivno najsiromašnijoj i smanjivanju aktivnosti na nutritivno
najbogatijoj hrani, dok se promena aktivnosti α-amilaze u odgovoru na povećanje
temperature sastoji u povećanju aktivnosti na hrani sa niskim sadržajem ugljenih
hidrata. Odgovor lipaze i kiselih fosfataza na nizak sadržaj proteina i visok sadržaj
ugljenih hidrata u hrani, kao i nutritivno siromašnu hranu sastoji se u povećanju
njihove aktivnosti, dok se aktivnost alkalne fosfataze sa porastom temperature
povećava i na hrani sa niskim sadržajem proteina i na hrani sa niskim sadržajem
ugljenih hidrata.
U odgovoru na delovanje temperature, pokazan je „obrnut obrazac“ promene
aktivnosti između endo i egzopeptidaze (elastaze i leucin aminopeptidaze), između
endo i egzokarbohidraze (-amilaze i -glikozidaze) i između alkalne i kiselih
fosfataza, kao i promena fenotipskih korelacija između pojedinih klasa enzima na
nepovoljnim temperaturama i suboptimalnom nutritivnom sadržaju hrane.
Uticaj temperature i kvaliteta hrane uočava se i na nivou promene ekspresije
genetičke varijabilnosti trajanja razvića, kao i preko značajne varijabilnosti
fenotipske plastičnosti u odgovoru na delovanje temperature. Na optimalnoj
temperaturi dolazi do porasta heritabilnosti mase larvi na nutritivno
najsiromašnijoj hrani, dok porast temperature smanjuje heritabilnost mase ako je
u hrani nizak sadržaj jednog ili oba nutrijenta. Genetičke korelacije izmedju
trajanja razvića i mase larvi u nepovoljnim uslovima životne sredine su negativne,
tj. larve koje karakteriše duže larveno razviće istovremeno imaju i manju masu,
dok u optimalnim uslovima nisu detektovane značajne korelacije između ovih
osobina. Većina genetičkih korelacije između sredina, kako za trajanje razvića, tako
i za masu larvi bila je pozitivna, što je očekivan rezultat za vrste generaliste. Sve
genetičke korelacije između sredina za trajanje razvića larvi su pozitivne i nisu
značajno različite od „1” tako da predstavljaju ograničenje za evoluciju fenotipske
plastičnosti. Genetičke korelacije između sredina za masu larvi su pozitivne i
značajno različite od „1” i, mada za masu larvi nije ustanovljena varijabilnost
fenotipske plastičnosti, evolucija plastičnosti je moguća usled značajnih razlika u
heritabilnosti između sredina.
Larve gubara mogu „profitirati“ u nepovoljnim uslovima nutritivno siromašne
hrane, jer je rezistentost gubara na temperaturni stres procenjena na osnovu
vremena preživljavanja, pokazala najveću vrednost u takvim uslovima. Nasuprot
tome, ograničavajući faktori preživljavanja su prethodna aklimacija na
(konstantno) povišenu temperaturu tokom ranih stupnjeva larvenog razvića i
visok sadržaj proteina i ugljenih hidrata u hrani. Suboptimalna temperatura
gajenja i hrana koju karakteriše najmanji odnos proteina u odnosu na ugljene
hidrate, kao i povećanje temperature gajenja na nutritivno najsiromašnijoj hrani,
značajno smanjuju sposobnost larvi gubara da se presvlače na stresnoj
temperaturi., 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.",
publisher = "Belgrade: University of Belgrade, Faculty of Biology",
journal = "University of Belgrade, Faculty of Biology",
title = "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.",
pages = "1-231",
url = "https://hdl.handle.net/21.15107/rcub_nardus_2094"
}