Increasing the biodiversity in plantations of trees is an important issue because plantations have replaced many natural and semi-natural ecosystems worldwide. Therefore, identifying appropriate management techniques and key factors for enhancing biodiversity in plantations is required. We surveyed butterfly assemblages along forest trails in both plantations and natural forests and measured various environmental variables, including canopy, sub canopy and shrub stem densities, percentage of deciduous trees, flower plant richness, host plant richness, canopy openness and distance to forest edge. We hypothesized that (1) flower and host plant richness increase with an increase in the percentage of deciduous trees and canopy openness; (2) butterfly richness and abundance increase with an increase in forest structural complexity, butterfly resources, canopy openness and distance to forest edge; (3) the responses of plants and butterflies to canopy openness differ in plantations and natural forests; and (4) in plantations, tree-feeding butterflies respond to canopy openness less strongly than herbaceous plant feeding butterflies do because of the low diversity of trees in plantations. Our results generally support these hypotheses. Butterfly resources and butterfly richness and abundance all increase with increasing canopy openness; however, the increases were usually more dramatic in natural forests than in plantations and other factors are less important. In plantations, herbaceous plant feeding butterflies responded to increasing canopy openness more strongly than tree-feeding butterflies. The results of the present study indicate the importance of sunlit forest trails in enhancing butterfly resources, butterfly richness and abundance in plantations. Because at the stand-level management is labour- and cost-intensive, labour- and cost-saving trail management options need to be explored further in terms their effectiveness in increasing biodiversity in plantations.
Flight activity in a pentatomid bug, Graphosoma lineatum, was measured under different photoperiodic conditions. Insects started flying 3 days after adult ecdysis and the percentage of flying adults became highest about 1 week after the ecdysis, regardless of the photoperiod. Under long day (18L : 6D), high flight activity was continued, whereas under short day (12L : 12D), most adults stopped flying when diapause was induced. In both photoperiods, a small number of adults showed flight of a long duration, longer than 30 minutes. Thus, no evidence was found relating the long flight to diapause. It is suggested that diapause adults of G. lineatum do not overwinter far from their breeding sites and thus there is no migration to hibernation sites. Also, the long flight is probably only a foraging flight, enabling the bugs to find their dispersed host plants.
The performance of the aphid-specific fungal pathogen Pandora neoaphidis was studied in relation to changes in herbivore resources for the pea aphid, Acyrthosiphon pisum, on different host plant species. Dose-response bioassays were conducted with A. pisum which had been reared on dwarf bean then inoculated with P. neoaphidis and returned to dwarf bean or inoculated and transferred to field bean, pea or lucerne. The smallest estimated median lethal concentration (LC50) was 7.7 conidia mm-2 (95% confidence interval 5.4-11.2) for aphids returned to dwarf bean, with LC50s of 13.0 (9.2-19.1) and 14.6 (10.2-21.5) conidia mm-2 for aphids transferred to field bean or pea, respectively. The LC50 when aphids were transferred to lucerne [2941.0 conidia mm-2 (237.3-2.1x109)] was greater than for the other three plants. In a subsequent experiment, A. pisum were reared on pea as well as dwarf bean for four generations before bioassays. The LC50 was 7.3 conidia mm-2 (4.4-12.4) for aphids reared and incubated on dwarf bean, compared to 13.3 (8.0-23.9) and 15.3 (8.8-29.9) conidia mm-2 when aphids were transferred between dwarf bean and pea, and vice versa, respectively. The LC50 for aphids reared then incubated on pea plants was 27.9 (15.8-57.3) conidia mm-2. Hence, the virulence of P. neoaphidis, measured by LC50, was greatest when A. pisum was reared and maintained on dwarf bean, the plant used for long-term routine culturing of the aphid in our facilities. In conclusion, virulence of P. neoaphidis was greater on plant species to which A. pisum had become adapted during long-term laboratory rearing. Plant resources may affect infection by P. neoaphidis and the fungal entomopathogen will have a greater impact on aphid herbivores which are not suffering physiological stress related to a change in host plant.
1_The maritime pine bast scale, Matsucoccus feytaudi Ducasse (Hemiptera: Matsucoccidae), occurs in the western part of the Mediterranean basin and is a sap sucking insect that feeds only on maritime pine (Pinus pinaster Aiton). It causes damage in SE France and Italy, where it was accidentally introduced. In Spain information is scarce and, moreover, almost nothing is known about the predators of this species. This study was designed to determine the seasonal trends in abundance of M. feytaudi and its major predators, which might help to improve the biological control of this pest in other areas. Natural P. pinaster stands in the Valencian Community (Spain) were surveyed in 2004. In addition, the seasonal trends in abundance of M. feytaudi and its natural enemies were monitored in three stands over a period of three years (2002, 2005 and 2006). The monitoring was carried by wrapping sticky tapes around tree trunks and using delta traps baited with sexual pheromone. The maritime pine bast scale was detected in all the stands surveyed. At almost all the sites surveyed, three species of predators were captured: Elatophilus nigricornis Zetterstedt (Hemiptera: Anthocoridae), Hemerobius stigma Stephens (Neuroptera: Hemerobiidae) and Malachiomimus pectinatus (Kiesenwetter) (Coleoptera: Malachiidae). The presence of M. pectinatus is noteworthy as this is the first record of this species as a possible predator of M. feytaudi. The results show that M. feytaudi, although differing in its phenology depending on the location, is univoltine in the study area. The prepupae, pupae and adults of M. feytaudi appeared between December and March in colder areas and between October and February in warmer areas. E. nigricornis nymphs are important predators of M. feytaudi, and were abundant when the scale insect (crawlers, prepupae, pupae, male and female adults) was present., 2_The flight period of E. nigricornis and the hemerobiid H. stigma ranged from May to October. However, these flight patterns did not correlate with the presence of the different stages of the bast scale (crawlers, prepupae, pupae, male and female adults) on the surface of tree trunks. The presence of M. pectinatus in large numbers in some stands suggests it might be an important natural regulator, which helps to keep M. feytaudi populations at low densities in the areas of Spain studied. This malachiid shows a strong kairomonal attraction to the sexual pheromone of M. feytaudi and its flight activity is significantly correlated with the presence of crawlers of bast scale., Eugenia Rodrigo ... [et al.]., and Obsahuje seznam literatury
Spring and summer composition and species richness of bruchid pre-dispersal seed predator assemblages associated with species of leguminous plants were monitored in a four-year non-experimental survey of 32 service areas along five highways in Hungary. The vegetation bands along highways (delimited by fences) were considered a special type of ecotone where herbaceous plants are exposed to regular mowing and therefore the composition of the vegetation there is very different from the adjacent vegetation. Altogether 57 herbaceous and woody species of leguminous plants were recorded at these sites, harbouring 20 autochthonous, 3 allochthonous, but established, and 4 recently introduced species of bruchid seed predators (Coleoptera: Chrysomelidae: Bruchinae). The species of leguminous plants recorded along highway verges during this project make up approximately one fourth of the Fabaceae in Hungary and of the bruchids ca. 80 % (!) of the species known to occur in Hungary. At half of the service areas, mowing decreased the species richness of leguminous plants compared to that recorded prior to mowing, but not that of their bruchid seed predators. However, the species composition of the bruchid assemblages before and after mowing changed substantially. Null-model analyses indicated a random organization of spring assemblages and a deterministic one of summer assemblages of bruchids; very likely a result of host-specificity constraints. Calculations of host specificity confirmed the narrow host range recorded for bruchids that emerged from the samples of plants, in spite of new host records, such as three and two Trifolium species for Bruchidius picipes and Bi. sp. prope varius sensu Anton, respectively, Oxytropis pilosa for Bi. marginalis and Vicia cracca for Bruchus brachialis. Our results show that a surprisingly high number of species of bruchids occur in highway margins, however, the management of the vegetation there prevents a substantial portion of the native bruchid fauna establishing permanent populations.