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Changes in ladybird communities along an altitudinal gradient
Matušová, Martina ; Kindlmann, Pavel (advisor) ; Martínková, Zdenka (referee)
Ladybugs are often used in biological control, because of their predatory way of life and potential ability to control many insect pests. So far, a number of studies was performed on this family, on their hunting strategies, other life history strategies, population dynamics, dependence of their distribution in time and space on the abundance of prey etc. However, the temporal changes in species composition and relative or absolute abundance of ladybugs were not yet examined along an altitudinal gradient. This is why I have focused my work on these dependencies. I tested the following hypothesis: overwintering sites in Coccinellidae are usually located at lower altitudes, where the individuals eventually attack their prey on the earliest budding trees; as season goes on, ladybugs follow the trends in environmental conditions and food and move to higher located sites; at the end of the season, ladybugs return back to their overwintering sites. In the research area in the Beskydy Mountains, 12 experimental sites were selected, evenly spaced along an elevational gradient of 350-482 m above sea level at each location. During the season, 12 measurements at two-week intervals were performed, each containing 2x300 sweeps. A total of 3064 of ladybug individuals were collected, belonging to 11 species. The...
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The food preferences of asian lady beetle Harmonia axyridis
Šenkeříková, P. ; Nedvěd, Oldřich
Survey of food preferences of Asian ladybird Harmonia axyridis included two-choice and no-choice tests. Wingless females of aphids Acyrthosiphon pisum, Aphis fabae cirsiiacanthoidis and Aphis sambuci were offered to twenty-four hours starving ladybirds. No-choice tests we conducted only with adults. We gave them 20 individuals of one aphid species and we found that ladybirds fed most number of A. pisum. In two-choice test, we combined pairs of studied species: A. f cirsiiacanthoidis x A. pisum, A. pisum x A. sambuci, A. sambuci x A. f cirsiiacanthoidis. We put 10 aphids of each of the two species combined into a plastic Petri dish and then we introduced one ladybird adult or larva. We made 20 replicates with adults. We found that there was statistical difference only in the combination A. sambuci vs. A. f cirsiiacanthoidis, where males consumed more individuals of the toxic aphid A. sambuci. For this combination, we then made 20 replicates with larvae who preyed in contrast with males more of the suitable food A. f cirsiiacanthoidis than toxic A. sambuci. We also studied the influence of contrasting background on food choice in adults. We used both tests and all combinations. We found that females did not prefer any aphid species, except for the black A. f cirsiiacanthoidis being consumed more often than the green A. pisum on black background. Because they consumed much more A. pisum in no-choice experiment on both backgrounds, the difference in choice experiment is very strong and its polarity surprising.
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Changes in ladybird communities along an altitudinal gradient
Matušová, Martina ; Kindlmann, Pavel (advisor) ; Martínková, Zdenka (referee)
Ladybugs are often used in biological control, because of their predatory way of life and potential ability to control many insect pests. So far, a number of studies was performed on this family, on their hunting strategies, other life history strategies, population dynamics, dependence of their distribution in time and space on the abundance of prey etc. However, the temporal changes in species composition and relative or absolute abundance of ladybugs were not yet examined along an altitudinal gradient. This is why I have focused my work on these dependencies. I tested the following hypothesis: overwintering sites in Coccinellidae are usually located at lower altitudes, where the individuals eventually attack their prey on the earliest budding trees; as season goes on, ladybugs follow the trends in environmental conditions and food and move to higher located sites; at the end of the season, ladybugs return back to their overwintering sites. In the research area in the Beskydy Mountains, 12 experimental sites were selected, evenly spaced along an elevational gradient of 350-482 m above sea level at each location. During the season, 12 measurements at two-week intervals were performed, each containing 2x300 sweeps. A total of 3064 of ladybug individuals were collected, belonging to 11 species. The...
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Factors affecting hatching rate of eggs of ladybirds
MAŠÍN, Vladislav
Hatching rate of eggs of ladybirds (Coleoptera: Coccinellidae) is affected by biotic and abiotic factors. Parental age, multiple matings, presence of male-killing agents, quantity and quality of food are the biotic factors. Temperature and wavelengths of light are the abiotic factors up to now tested. We reviewed these above mentioned factors that authors of diverse studies measured,and in addition, we retrieved data on fecundity and its relation to hatching rate. In 7 cases, hatching rate was significantly positively correlated to fecundity, in another 5 cases, there was no clear relationship. We argue that in unsuitable conditions visualized by low fecundity, female ladybirds lay higher proportion of infertile eggs as so called trophic eggs for feeding the neonate larvae.
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Chemical defence of ladybirds against ants
ROZSYPALOVÁ, Adéla
This work studied distastefulness of alkaloids of eight ladybird species (Adalia bipunctata, Calvia quatuordecimguttata, Coccinella septempunctata, Cynegetis impunctata, Exochomus quadripustulatus, Halyzia sedecimguttata, Harmonia axyridis, Psyllobora vigintiduopunctata) for ants Lasius niger. The reaction to extracts of various ladybird species isn´t corelated with their size. There is a weak relationship of distastefulness on ladybird coloration.
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