Pestitsiidi dimetoaat mõju nosematoosiga nakatatud meemesilaste ainevahetuse tasemele ja suremusele
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Kuupäev
2019
Kättesaadavus
4.09.2019
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Tolmeldajate arvukuse langust on täheldatud üle maailma juba üle kümne aasta. Nende
arvukuse vähenemine on ohtlik loodusliku mitmekesisuse säilimise, kuid ka suureneva
rahvastiku toiduga varustamise seisukohalt. Tolmeldajate arvukuse vähenemise üheks
põhjuseks loetakse nii intensiivses põllumajanduses, haljastuses kui ka infrastruktuuride
hoolduses kasutatavaid taimekaitsevahendeid. Teiseks tolmeldajaid, sealhulgas
meemesilasi, negatiivselt mõjutavaks faktoriks on haigused, patogeenid ja viirused.
Viimasel ajal on enim tähelepanu pöörama hakatud meemesilaste tervist mõjutavate
stressifaktorite koostoimetele. Kirjanduses on välja toodud, et just erinevate
stressifaktorite koostoimel on mesilaste suremus oluliselt kõrgem kui üksikute faktorite
puhul.
Antud uurimistöö eesmärgiks oli välja selgitada meemesilaste (Apis mellifera) seas
levinud haiguse nosematoosi tekitajate Nosema apis ja N. ceranae koosmõju
taimekaitsevahendi dimetoaadiga. Käesolevas töös kasutati haigustekitajate ja
taimekaitsevahendi koosmõju hindamiseks meemesilaste suremuse ja ainevahetuse taseme
muutuste jälgimist.
Katse tulemustest selgus, et väga madal dimetoaadi kontsentratsioon, mida katses kasutati,
ei avalda mõju meemesilaste ainevahetuse tasemele. Samuti ei avalda ainevahetusele
mõju kummagi nosematoosi nakkus ega selle koostoime dimetoaadiga. Taimekaitsevahendi dimetoaadi negatiivne mõju avaldus meemesilaste suremuses, kus
koostoimes nosematoosi tekitajaga N. apis ilmnes hüppeline tõus, kuigi alates 17.
katsepäevast. N. apis ise kontrollist erinevat suremust ei põhjustanud. N. ceranae ja kahe
haigustekitaja koosmõju olid meemesilastele rängemad taluda, kuid nende puhul
dimetoaadi mõju eraldi välja ei tulnud.
The decline in pollinator abundance has been observed worldwide in last decades. The decrease in their abundance is dangerous for the preservation of natural diversity, but also for increasing the supply of food to the growing human population. Decrease in pollinator abundance is at least partly due to plant protection products used in intensive farming, landscaping and infrastructure maintenance. The second factor that negatively affects pollinators, is the increasing spread of bee diseases, pathogens and viruses. Lately the greatest attention has been paid to the interactions between different stress factors affecting the health of honeybees. It has been pointed out that the combination of these are more detrimental than single factors. The aim of this study was to identify the risk of the combined effect of Nosema apis and N. ceranae, common causes of nosematosis among honeybees (Apis mellifera), with an insecticide dimethoate. In this work, a honeybee mortality monitoring and measuring metabolic rate were used to assess the effects of interactions between pathogens and the plant protection product. The results showed that the low concentration of dimethoate used in the experiment had no substantial effect on honeybee metabolic rate. The metabolic rate was also not affected by the nosematosis infection nor with its interaction with dimethoate. The mortality increased because of coinfection of the two pathogens and also because of N. ceranae alone. The effect of dimethoate occurred, however, only with N. apis, which alone had no effect on individual honeybee mortality.
The decline in pollinator abundance has been observed worldwide in last decades. The decrease in their abundance is dangerous for the preservation of natural diversity, but also for increasing the supply of food to the growing human population. Decrease in pollinator abundance is at least partly due to plant protection products used in intensive farming, landscaping and infrastructure maintenance. The second factor that negatively affects pollinators, is the increasing spread of bee diseases, pathogens and viruses. Lately the greatest attention has been paid to the interactions between different stress factors affecting the health of honeybees. It has been pointed out that the combination of these are more detrimental than single factors. The aim of this study was to identify the risk of the combined effect of Nosema apis and N. ceranae, common causes of nosematosis among honeybees (Apis mellifera), with an insecticide dimethoate. In this work, a honeybee mortality monitoring and measuring metabolic rate were used to assess the effects of interactions between pathogens and the plant protection product. The results showed that the low concentration of dimethoate used in the experiment had no substantial effect on honeybee metabolic rate. The metabolic rate was also not affected by the nosematosis infection nor with its interaction with dimethoate. The mortality increased because of coinfection of the two pathogens and also because of N. ceranae alone. The effect of dimethoate occurred, however, only with N. apis, which alone had no effect on individual honeybee mortality.
Kirjeldus
Magistritöö
Põllumajandussaaduste tootmise ja turustamise õppekaval
Märksõnad
magistritööd, meemesilased, dimetoaat, ainevahetus, suremus