Urban rain pools: seasonal dynamics and entomofauna in a park of Buenos Aires

We describe the seasonal variations of the insect community of the rain pools in a park of Buenos Aires during a 1-year period, based on a weekly sampling programme. We also analyse the relationships between the observed biotic patterns and some physical and meteorological variables. Four periods, fairly coincident with the seasons of the year, were graphically identified as functions of temperature, rainfall, flooded area, number of rain pools, depth and taxonomic richness. A total of 45 insect taxa was identified: 18 Coleoptera, 15 Diptera, 9 Heteroptera, 1 Ephemeroptera and 2 Odonata. Culicidae represented 76% of the pooled abundance of insects, probably related to their rapid development before the pools dry up. Taxonomic richness was maximum at the end of the summer (32), in coincidence with maximum rainfalls and temperatures. Inversely, the minimum richness (2) was recorded during the spring drought. Richness was positively correlated to the flooded area and to the number of pools on each sampling date. The species recorded throughout the study period were: Aedes albifasciatus, Culex eduardoi, Culex pipiens, Liodessus sp., Rhantus signatus signatus, Tropisternus setiger, Tropisternus lateralis limbatus and Sigara platensis. Some of the species recorded are considered pioneer in temporary habitats. Both coleopterans and heteropterans are likely to persist in the park through repeated colonisation from more permanent habitats. Habitat duration and flooded area were positively correlated to richness in each one of the rain pools.     

Host range of the parasite Strelkovimermis spiculatus (Nematoda: Mermithidae) in Argentina mosquitoes

Strelkovimermis spiculatus ( Poinar and Camino 1986 ) is a nematode parasite of mosquitoes isolated from the Neotropical region. We investigated the host range of this parasite in mosquito populations for a better understanding of the dynamics of temporary breeding sites. Five grassy‐pool habitats filled by rainwater were sampled from the summer 2007 through the fall 2008. Eight mosquito species were collected: Anopheles albitarsis, Culex chidesteri, Culex dolosus, Culex maxi, Aedes albifasciatus, Psorophora ciliata, Psorophora cyanescens, and Psorophora albigenu. Six of these species were parasitized: Cx. chidesteri, Cx. dolosus, Cx. maxi, Ae. albifasciatus, Ps. ciliata, and Ps. cyanescens. The occurrence of this mermithid in natural mosquito populations was increased from the end of winter to the end of the spring. Prevalence ranged from 11% to 100%. High levels of infections were registered only in Ae. albifasciatus larvae, the most abundant mosquito species (95%), followed by Cx. dolosus (2.7%). Strelkovimermis spiculatus completed its development in all infected mosquito larvae. The presence of S. spiculatus in six natural mosquito populations increases the number of susceptible species to 24.     

Effects of crowding on populations of Aedes albifasciatus larvae under laboratory conditions

Aedes (Ochlerotatus) albifasciatus(Macquart 1838) (Diptera: Culicidae) is a neotropical flood water mosquito, incriminated as the main vector of the western equine encephalitis virus, and which affects beef and milk production in central Argentina. The short time required to hatch and develop from egg to adult, usually in temporary pools, suggests a strategy which allows for exploitation of transient pools, thus evading predation and interspecific competition. Under these conditions intra specific competition could represent a major density-dependent source of larval mortality, but the relative importance of density-dependent regulation of mosquito populations has generated controversy. Therefore we examined the effects of larval density on basic population characteristics of Ae. albifasciatusin the laboratory. Larvae were obtained by synchronous hatching of eggs laid by field-trapped females. Emerging larvae (L1) were used to build cohorts of different initial densities, kept in plastic trays with 400 ml of distilled water, and food supplied daily during the first 10 days (0.1 g per larvae day^–1). Age-specific development time and specific and relative mortality were estimated, and their relation to initial larval density was assessed through linear and non-linear regressions and correlation analysis. First hatching was registered 3 h after flooding the eggs. Higher levels of pre-adult mortality were detected in groups with higher densities. Specific mortality and average time to enter a stage of L1 to L3 could directly be related to initial larval density, but no significant relations were found for L4 and pupae. Results suggest that crowding could be a factor capable of regulating the density of natural populations of Ae. albifasciatus.     

Detection of Orthobunyavirus in mosquitoes collected in Argentina

Bunyamwera virus (BUNV) (Bunyaviridae, genus Orthobunyavirus, serogroup Bunyamwera) is considered an emerging pathogen for humans and animals in American countries. The CbaAr‐426 strain of BUNV was recovered from mosquitoes Ochlerotatus albifasciatus (Diptera: Culicidae) collected in Córdoba province (Argentina), where serological studies detected high seroprevalences in humans and animals. Molecular detection of Orthobunyavirus was performed in mosquitoes collected in Córdoba province. Seventeen mosquito pools of Oc. albifasciatus, Ochlerotatus scapularis and Culex quinquefasciatus (Diptera: Culicidae) showed positive results; four of these positive pools, all of Oc. scapularis, were sequenced. All amplicons grouped with BUNV in the Bunyamwera serogroup. The findings highlight the circulation of BUNV in Córdoba province and represent the first report of BUNV‐infected Oc. scapularis mosquitoes in Argentina.     

Nuclear and cytoplasmic gene control of resistance to loose smut (Ustilago tritici (Pers.) Rostr.) in wheat (Triticum aestivum L.)

Summary Using disomic chromosome substitution lines based on the susceptible wheat cultivar Chinese Spring, loose smut resistance of wheat cultivars Hope and Thatcher was shown to be conferred in each case by a single dominant major gene carried on chromosome 7 A (Hope) or 7 B (Thatcher). Partial resistance was determined by genes on an additional eight Hope or seven Thatcher chromosomes, and similarities were evident between the partial resistance genotypes ofHope and Thatcher. Chinese Spring exhibited a mean infection value of approximately 50%, indicating a significant level of partial resistance, which was found to be due, in part, to genes on the homoeologous chromosome arms 1 As, 1 Es and 1 Ds, and to cytoplasmic genes. Substitution of the Chinese Spring nucleus into the cytoplasm of Aegilops squarrosa, Ae. variabilis or Ae. mutica resulted in increased susceptibility to Ustilago tritici. Several alloplasmic lines of the resistant wheat cultivars Selkirk and Chris exhibited race-specific susceptibility to U. tritici.     

Mast-seeding in the cycad genus Encephalartos: a test of the predator satiation hypothesis

Mast-seeding behaviour was monitored in 18 populations of eight species of the African cycad genus Encephalartos between 1988 and 1991. The coefficient of variation (V) in annual cone production for each population ranged between 88 and 200, indicating large fluctuations in reproductive effort between years. Data were collected to determine whether mast-seeding reduced levels of predispersal seed predation by satiating seed predators in mast years and whether it resulted in a reproductive advantage over plants which reproduced more frequently. Masting intensity was greatest in those populations in which individual plants suffered the highest levels of predispersal seed predation in years when only a few plants produced seeds. The principal seed predators were two congeneric weevil species, Antliarhinus zamiae and A. signatus, which develop exclusively on cycad seeds. The lowest intensity of mast-seeding was recorded for cycad populations with low levels of seed predation and in which A. zamiae and A. signatus occurred only in low numbers or were entirely absent. Larger seed crops appeared to result in lower levels of seed predation by A. zamiae and A. signatus in four populations of E. altensteinii, and differences in seed crop size accounted for 48–66% of variation in levels of seed predation in populations of five cycad species. In one population of E. altensteinii, lower levels of seed predation in plants reproducing periodically resulted in a reproductive advantage over plants reproducing more frequently. These results are consistent with the predator satiation hypothesis. However, in most cycad populations, numbers of seed predators did not appear to decrease significantly after a period of 2–8 years between reproductive episodes and, in two of three populations examined, periodic reproduction did not increase the number of seeds surviving to dispersal over a 4-year period. These results are interpreted to mean that periodic reproduction has not evolved in response to selection imposed by seed predators, but that selection may favour those plants which experience lower levels of seed predation by coning in synchrony with the majority of plants in the population.     

Diving beetle assemblages of flooded wetlands in relation to time,wetland type and Bti-based mosquito control

We investigated the abundance and taxonomic composition of the aquatic predatory insect fauna, with focus on adult diving beetles (Coleoptera: Dytiscidae), in eight temporary flooded wet meadows and two alder swamps in the River Dalälven floodplains, central Sweden from 2002 to 2006. Diving beetles are generalist predators and often abundant in various waters, including temporary wetlands. In the River Dalälven floodplains, recurrent floods induce massive hatching of flood-water mosquitoes (Diptera: Culicidae), which constitute a superabundant patchy and irregular food resource for aquatic predatory insects. Our aims were (1) to characterize the assemblage of adult diving beetles occurring in the wetlands during floods in relation to time and wetland type and (2) to evaluate the effect on the aquatic predator assemblage of strongly reducing the abundance of a potential prey, flood-water mosquito larvae with Bacillus thuringiensis var. israelensis (Bti) during floods. We found diving beetles to be the dominating aquatic predatory insect taxa in all 10 wetlands. There was a difference in Dytiscidae species richness but not in diversity between wet meadows and alder swamps after rarefaction. The cluster analysis based on dytiscid species and abundances showed very high similarities between the wetlands. The variance component analysis was unable to distinguish any factor that could explain more than 7.4% of the variation in the dytiscid species assemblages. The only effect of Bti-treatment against flood-water mosquito larvae, potential food for the predatory dytiscids, was a slight increase in abundance of the medium-sized dytiscid species. Our results are in accordance with previous studies, suggesting that irregular and recurrent flood dynamic structure the dytiscid fauna more than food limitations and environmental factors.     

Bellevalia ciliata (Cyr.) Nees (Hyacinthaceae) neu für Bulgarien

(Bellevalia ciliata was recorded in north-east Bulgaria south of the Dobrudsha, within field and steppe vegetation. Vegetation records and a distribution map are presented. Based on taxonomic studies it is proposed to combineB. ciliata, B. sarmatica (Pall.) Wor. andB. speciosa Wor. under the oldest nameB. ciliata (Cyr.) Nees.     

Predation of cotton leafworm first instar larvae,Alabama argillacea [Lep.: Noctuidae]

Natural predation first instar larvae of the cotton leafworm (CLW)A. argillacea was studied in cotton fields in Jaboticabal, Sao Paulo State, Brazil, during 1986. The presence of naturally occurring arthropod predators showed a first instar larvae predation rate of 78.6 and 88.9% after 24 h and 48 h of exposure, respectively. A predator prey ratio of 1∶1 (1 CLW key predator per 1 prey/plant) maintained a level of no more than 1 CLW small larvae per plant. The most evident arthropod predators in the studied fields were: beetles (Coleoptera: Coccinellidae), antsPheidole sp. andConomyrma sp.;Dermaptera Doru lineare (Eschs);Hemiptera Geocoris sp., andOrius insidiosus Say; and the spidersTheridion volubile, Chrysso pulcherrima, Misumenops sp.,Chiracanthium sp., andOxyopes salticus Hentz.      

Diving beetles of the genus Liodessus Guignot, 1953 in Colombia,with description of three new species (Coleoptera: Dytiscidae)

The Colombian species of the diving beetle genus Liodessus Guignot, 1939 Guignot, F. (1939), ‘Contribution à l’étude des Bidessus’, Bulletin de la Société d’Étude des Sciences Naturelles de Vaucluse, 10(4), 51–61. [Google Scholar] are revised. Liodessus bogotensis Guignot, 1953 Guignot, F. (1953), ‘Trente-neuvième note sur les hydrocanthares’, Revue Française d’Entomologie, 20, 109–117. [Google Scholar] is re-described. Three higher altitude species are new to science: Liodessus azufralis sp. n., L. quillacinga sp. n. and L. quimbaya sp. n. We also introduce two new subspecies, L. quillacinga cochaensis ssp. n. and L. quillacinga cumbalis ssp. n. We delineate the species using morphological structures such as male genital structure and beetle size, shape and colour pattern. Mitochondrial cox1 sequence data provided an additional character source. All the new species occur on higher altitudes above 2700 m and were collected in shallow, exposed peatland pools and puddles, mostly in Páramo. Liodessus obscurellus (LeConte, 1852), not yet recorded from Colombia, is included into the key due to its presence in nearby Costa Rica and Ecuador. The known distribution and habitat preferences of each species are outlined briefly.     

Density-dependent effects of multiple predators sharing a common prey in an endophytic habitat

Multiple predator species feeding on a common prey can lead to higher or lower predation than would be expected by simply combining their individual effects. Such emergent multiple predator effects may be especially prevalent if predators share feeding habitat. Despite the prevalence of endophagous insects, no studies have examined how multiple predators sharing an endophytic habitat affect prey or predator reproduction. We investigated density-dependent predation of Thanasimus dubius (Coleoptera: Cleridae) and Platysoma cylindrica (Coleoptera: Histeridae) on a bark beetle prey, Ips pini (Coleoptera: Scolytidae), in a laboratory assay. I. pini utilize aggregation pheromones to group-colonize and reproduce within the stems of conifers. T. dubius and P. cylindrica exploit these aggregation pheromones to arrive simultaneously with the herbivore. Adult T. dubius prey exophytically, while P. cylindrica adults enter and prey within the bark beetle galleries. Larvae of both predators prey endophytically. We used a multiple regression analysis, which avoids confounding predator composition with density, to examine the effects of varying predator densities alone and in combination on herbivore establishment, herbivore reproduction, and predator reproduction. Predators reduced colonization success by both sexes, and decreased I. pini reproduction on a per male and per female basis. The combined effects of these predators did not enhance or reduce prey establishment or reproduction in unexpected manners, and these predators were entirely substitutable. The herbivores net replacement rate was never reduced significantly below one at prey and predator densities emulating field conditions. Similar numbers of each predator species emerged from the logs, but predator reproduction suffered from high intraspecific interference. The net replacement rate of P. cylindrica was not affected by conspecifics or T. dubius. In contrast, the net replacement rate of T. dubius decreased with the presence of conspecifics or P. cylindrica. Combinations of both predators led to an emergent effect, a slightly increased net replacement rate of T. dubius. This may have been due to predation by larval T. dubius on pupal P. cylindrica, as P. cylindrica develops more rapidly than T. dubius within this shared habitat.     

Hydrotrupes chinensis Nilsson, 2003 (Coleoptera: Dytiscidae): new records, (re)description of adult and larva,and notes on its biology

Abstract

Hydrotrupes chinensis Nilsson, 2003 Nilsson, A.N. (2003), ‘Dytiscidae. XII. A New Species of Hydrotrupes Sharp from China, an Example of Pacific Intercontinental Disjunction (Coleoptera)’, in Water Beetles of China (Vol. 3), eds. M.A. Jäch and L. Ji, Vienna: Zoologische-Botanische, Gesellschaft, pp. 284–297. [Google Scholar] described from the holotype collected in Anhui Province, China, is newly recorded from three localities in Guangdong Province, ca. 750?km southwest from the type locality. The species seems to inhabit hygropetric habitats exclusively, with diurnal larvae and nocturnal adults hidden under stones or in cracks in rock during the day; when disturbed, the adults readily jumped off the rock surface. The adult is redescribed. The larvae are described and illustrated for the first time, with detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, last abdominal segment, and urogomphi. Whereas similar morphologically to the Nearctic endemic Hydrotrupes palpalis Sharp, 1882 Sharp, D. (1882), ‘On Aquatic Carnivorous Coleoptera or Dytiscidae’, Scientific Transactions of the Royal Dublin Society, 2, 179–1003. [Google Scholar], the first instar larva of H. chinensis distinguishes by presence of six lamellae clypeales, two additional spine-like setae both on the last abdominal segment and urogomphomere 1, and the strongly developed egg bursters.     

Nematodes from the Strait of Magellan and the Beagle Channel (Chile): the genera Cervonema and Laimella (Comesomatidae: Nematoda)

Five species of Cervonema and four species of Laimella are described from the Strait of Magellan and the Beagle Channel, Chile, six species of which are new to science. Cervonema chilensisn. sp. and Cervonema hermanin. sp. are separated from other known species of Cervonema by a short cervical region (less than one head diameter from the front end to the anterior border of the amphids). Cervonema chilensisn. sp. is characterised by a tail length of 5 anal diameters with posterior half filiform; Cervonema hermani n. sp. is characterised by a tail length of 6–9 anal diameter and posterior part (75%) cylindrical. Cervonema shiaen. sp. is characterised by the cephalic seta 4 m long, amphids 9–10 m in diameter; spicules 16 m long and 0.8–0.9 abd; tail 4.7–5.4 anal diameter and 50% posterior part filiform; 4–5 minute precloacal supplements. Laimella subterminatan. sp. is characterised by the subterminal position of the buccal cavity which separates it from the other species of the genus. Laimella annaen. sp. is characterised by the head diameter 9–11 m, cephalic setae and external labial setae 9 + 5 m long, respectively, amphids 7 m in diameter; spicules 28–30 m long; tail 14–17 anal diameter and posterior part (75%) filiform; 5 precloacal supplements. Laimella sandraen. sp. is very close to Laimella annaen.sp. in having similar cephalic sensilla, amphids and spicules. Laimella sandraen. sp., however, can be separated from L.annaen. sp. by the shape of head and the structure of sperm cells, the total body length and the cylindrical part of tail. Cervonema papillatum Jensen, 1988, C. tenuicauda (Stekhoven, 1950) and L. longicauda Cobb, 1920 are found in this area as well. The key of all known species of Cervonemaand Laimellais presented.     

Taxonomic review of the genus Copelatus Erichson (Coleoptera: Dytiscidae) in Korea

A taxonomic review of the genus Copelatus Erichson (Coleoptera: Dytiscidae) in Korea is presented. In the present study, five species of Copelatus are recognized from Korea, including one unrecorded species, C. kammuriensis. We provide a key to the Korean species of Copelatus, diagnosis of one unrecorded species, habitus photographs, scanning electron micrographs of the elytron, and illustrations of the aedeagus.     

Prevalence of tick-borne pathogens in ixodid ticks (Acari: Ixodidae) collected from European wild boar (<Emphasis Type="Italic">Sus scrofa</Emphasis>) and Iberian red deer (<Emphasis Type="Italic">Cervus elaphus hispanicus</Emphasis>) in central Spain

Emerging tick-borne diseases of humans and animals have occurred frequently during the past 30 years. These disease outbreaks appear to result from changes in the distribution of tick and vertebrate hosts, and the introduction of humans and domestic animals into tick–pathogen–wildlife cycles. Use of molecular technologies now available for identification of pathogens in ticks can provide valuable information that allows for risk analysis of emerging tick-borne diseases. In this study, the prevalence of selected pathogens in ticks collected in six locations in central Spain from the major wild ungulate species, European wild boar (Sus scrofa) and Iberian red deer (Cervus elaphus hispanicus), was determined by PCR. Tick species collected included Ixodes ricinus, Dermacentor marginatus, Rhipicephalus bursa and Hyalomma m. marginatum. Pathogens identified in ticks included piroplasmids, Anaplasma spp., Ehrlichia spp. and Rickettsia spp. Piroplasmids were identified in all tick species except I. ricinus. Ehrlichia spp. were detected in all tick species and collection locations, while Rickettsia spp., which proved to be R. slovaca and a recently identified Rickettsia sp. DnS28, were identified only in D. marginatus. A. marginale and A. phagocytophilum were detected in D. marginatus, R. bursa and Hy. m. marginatum. Concurrent infections of these pathogens were frequently observed in ticks. Notably, A. phagocytophilum, which is infective for a broad host range that includes humans and domestic and wild animals, was identified in ticks from all collection locations. The variety of ticks and tick-borne pathogens demonstrated in this study suggests a risk in central Spain for the emergence of tick-borne diseases in humans and domestic animals.     

Modeling flight activity and population dynamics of the pine engraver, Ips pini, in the Great Lakes region: effects of weather and predators over short time scales

Ascertaining the relative effects of factors such as weather and predation on population dynamics, and determining the time scales on which they operate, is important to our understanding of basic ecology and pest management. In this study, we sampled the pine engraver Ips pini (Say) (Coleoptera: Scolytidae) and its predominant predators Thanasimus dubius (F.) (Coleoptera: Cleridae) and Platysoma cylindrica (Paykull) (Coleoptera: Histeridae) in red pine plantations in Wisconsin, USA, over 2 years. We sampled both the prey and predators using flight traps baited with the synthetic aggregation pheromone of I. pini. Flight models were constructed using weather variables (temperature and precipitation), counts of bark beetles and their predators, and temporal variables to incorporate possible effects of seasonality. The number of I. pini per weekly collection period was temperature dependent and decreased with the number of predators, specifically T. dubius in 2001 and P. cylindrica in 2002. The number of predators captured each week was also weather dependent. The predators had similar seasonal phenologies, and the number of each predator species was positively correlated with the other. Including a term for the number of prey did not improve the model fits for either predator for either year. Our results suggest that exogenous weather factors strongly affect the flight activity of I. pini, but that its abundance is also affected by direct density-dependent processes acting over weekly time scales. Adult predation during both colonization and dispersal are likely processes yielding these dynamics.     

Shifts in aquatic macroinvertebrate biodiversity associated with the presence and size of an alien crayfish

To investigate the effects of Procambarus clarkii on macroinvertebrate diversity, we conducted a mesocosm experiment simulating small pools in rice field pads after the rice season. We hypothesized that crayfish predation would negatively impact macroinvertebrate diversity, and the magnitude of this impact should vary with the size of P. clarkii. We conducted a short-term mesocosm experiment to determine macroinvertebrate diversity in the presence of three size classes and in the absence of crayfish, as well as the diet composition of crayfish from the three size classes. At the end of the experiments, the diet of crayfish was composed of the most available taxa (Culicidae, Chironomus, Tanytarsini and Orthocladinae). These results also show evidence that, in confined areas, crayfish are important predators of major rice pests such as rice Chironominae larvae. Macroinvertebrate diversity was negatively affected by crayfish presence, but the effect was inversely proportional to crayfish size. The highest diversity index was obtained in the absence of P. clarkii, and juvenile crayfish significantly reduced macroinvertebrate diversity. Thus, the impact of P. clarkii on aquatic macroinvertebrates is size dependent and may be relevant in small pools formed in rice field pads from early autumn to late winter. Overall, our findings suggest that the negative effects of P. clarkii on macroinvertebrate diversity may be particularly strong in local natural assemblages confined to puddles of water or small ponds in wetland areas.     

Construction of insertion mutants of Synechocystis sp. PCC 6803: evidence for an essential function of subunit IV of the cytochrome b6/f complex

The gene encoding subunit IV of the cytochrome b₆/f complex (petD) has been isolated from a genomic library of the unicellular cyanobacterium Synechocystis sp. PCC 6803. The coding region consists of 480 nucleotides and can code for a polypeptide with a molecular weight of 17.5 kDa. The deduced amino acid sequence shows high identity with the corresponding sequences of both the photoautotrophic prokaryote Nostos sp. PCC 7906 as well as of lower and higher photoautotrophic eukaryotes (e.g. Chlorella protothecoides, Nicotiana tabacum). Transformation of Synechocystis sp. PCC 6803 with a plasmid containing the cloned petD gene in which the coding sequence is interrupted by the aminoglycoside 3-phosphotransferase gene (aph) from Tn903 resulted in the formation of km resistant transformants. The molecular analysis of independent transformants revealed that all clones were merodiploid containing both uninterrupted wild-type as well as interrupted mutant petD copies. Approaches to segregate these two genomes were unsuccessful implying an essential function of the petD gene product in Synechocystis sp. PCC 6803.Abbreviations aph aminoglycoside 3-phosphotransferase - cpDNA chloroplast DNA - km kanamycin - PSI photosystem I - PSII photosystem II     

Estimation of mortality by entomophages on exotic Harmonia axyridis versus native Adalia bipunctata in semi-field conditions in northern Italy

A semi-field experiment was carried out in two peach orchards in northern Italy to assess mortality due to predators and parasitoids on the exotic coccinellid Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) in comparison with the native coccinellid Adalia bipunctata L. (Coleoptera: Coccinellidae). The experiments were conducted in cages to avoid the possible escape of the exotic ladybird (not yet established in Italy). Two kinds of cage experiments were included: ‘exclusion cages’ (access by walking predators impeded) and ‘free cages’ (walking predators free to enter). The cages, containing all the stages of the two ladybird species, were placed in two localities and left for 24 h. All ladybird stages used for the semi-field experiments came from a laboratory rearing. The eggs of H. axyridis experienced less mortality than those of A. bipunctata. The ant workers were the most frequent predators in ‘free cages’ but A. bipunctata cannibalism on eggs was also detected. Larvae of both coccinellid species were predated equally but larval predation of L1 and L2 was higher in comparison to predation of L3 and L4. Pupae and adults of both exotic and native ladybirds were never attacked by predators. Predation on younger larval stages was higher in the ‘free cages’ in comparison with ‘exclusion cages’. No ladybird parasitisation was observed. The ‘free cage’ technique seems to provide a standardised and realistic estimation of predation impact but more studies are needed to evaluate ladybird parasitisation in semi-field conditions.