Variation of density‐dependence with spatial scale in the leaf‐mining fly Liriomyza commelinae (Diptera: Agromyzidae)

  title={Variation of density‐dependence with spatial scale in the leaf‐mining fly Liriomyza commelinae (Diptera: Agromyzidae)},
  author={Brian E. Freeman and David C. Smith},
  journal={Ecological Entomology},
Abstract. 1. Mortality imposed on the leaf mining fly, Liriomyza commelinae (Frost) was studied at three spatial levels: (1) the leaf, (2) the stem, and (3) a metre quadrat of the food plant. 

The effect of predators on the abundance of the Macadamia Nutborer ( Ecdytolopha torticornis )

Predation was found to significantly reduce the abundance of nutborer larvae, and the fire ant Solenopsis geminata F. solenopsis was considered to be the most important predator.

Density effect and intraspecific competition in a leaf-mining moth on bamboo leaves

The density threshold could be an indicator of the balance between intraspecific competitive detriments and conspecific aggregation benefits; however, the validity of the threshold density hypothesis requires further testing and confirmation.

Population studies and conservation of Jamaica’s endangered swallowtail butterfly Papilio (Pterourus) homerus

This is an 18-year study of the endangered Papilio (Pterourus) homerus, adding substantial information to the authors' scanty knowledge of its ecology, and believes this is an artefact due to collectors working only at the periphery of its distribution.

Potential impact of Coleomegilla maculata predation on adaptation of Leptinotarsa decemlineata to Bt‐transgenic potatoes

Results showed that C. maculata predatory behavior could decrease the rate at which L. decemlineata adapted to Bt‐toxins if plot‐to‐plot mixed‐plantings were used and that egg consumption was inversely related to egg mass density at the smallest and the largest spatial scales tested.

Commelina Species - A Review of its Weed Status and Possibilities for Alternative Weed Management in the Tropics

It is concluded that successful management of Commelina species and their biotypes can only be achieved by a multi-component approach.

Spatial scale of aggregation in three acarine predator species with different degrees of polyphagy

This is the first empirical evidence demonstrating the relation between the degree of polyphagy and the spatial scale of aggregation, and it is concluded that both the prey patch size and predator foraging range are important for analyzing spatial scales of predator aggregation.

Density effects at multiple scales in an experimental plant population

Plant population patterns may reflect density effects interacting at different characteristic scales, and generalizations about density-dependence in spatially structured populations may be misleading if they fail to recognize that density is scale-dependent.

Parasitism of Natural Populations of Liriomyza helianthi Spencer and Calycomyza platyptera (Thomson) (Diptera: Agromyzidae)

The population dynamics and parasitoid assemblages of two leafminers, Liriomyza helianthi Spencer and Calycomyza platyptera (Thomson) (Diptera: Agromyzidae), were examined over a 3-year period and found the potential for exchange of natural enemies among habitats, potentially enhancing pest control in agricultural areas.

The population dynamics of a hybrid zone in the Alpine grasshopper Podisma pedestris : an ecological and genetic investigation.

Computer simulations show that the observed position of the cline is consistent with that expected from both direct density esti­ mates, and densities inferred from a vegetation survey, and that these estimates are robust.

Density-related mortality in Cameraria hamadryadella (Lepidoptera: Gracillariidae) at epidemic and endemic densities

The results suggest that natural enemies are not responsible for the decline in abundance of C. hamadryadella observed between 1984 and 1990, however, starvation possibly arising from host resistance and, secondarily, intraspecific competition could account for the observed decline.




1. Life‐table data for 14 species of Lepidoptera are analysed by the k‐factor technique of Varley & Gradwell (1960). Two factors are shown to be of particular importance in determining fluctuations

Inverse density dependent parasitism in a patchy environment: a laboratory system

Two species of parasitoids attacking the bruchid beetle show marked inverse density dependent relationships between per cent parasitism and host density per patch.

Parasitism of a frugivorous fly, Rhagoletis cornivora, by the wasp Opius richmondi: relationships to fruit and host density

This work assessed experimentally the effect of fruit density on attack of herbivores by natural enemies through characteristics of both host plants and herbivorous insects.

Studies on the Natural Enemy Complex of the Holly Leaf-Miner: The Effects of Scale on the Detection of Aggregative Responses and the Implications for Biological Control

The species imposing spatially density dependent mortality (C. gemma) has been used as an effective biological control agent against the holly leaf-miner in Canada and is discussed in relation to two problems, namely that of detecting an aggregative response by natural enemies in the field, and what constitutes a 'patch'.

Spatial variations in egg density and the intensity of parasitism in a neotropical chrysomelid (Cephaloleia consanguinea)

Despite this inverse relationship between the overall probability of parasitism and egg density per leaf, a model based on the binomial distribution provides a good description of the spatial aspects of this host—parasitoid interaction.

Egg Density and the Intensity of Paratism in Prokelisia Marginata (Homoptera: Delphacidae)

Prokelisia marginate (Homoptera:Delphacidae) is the most common homopteran in- habiting salt marsh cord grass in northwest Florida, and periodic tidal inundation of S. alterniflora may disrupt parasitoid searching and affect parasitism rates as a function of density.

The ecology of two West Indian species of mud‐wasps (Eumenidae: Hymenoptera)

Rainfall was a limiting factor in both aspects of the ecology of the neotropical mud-wasps Zeta abdominale and Z. canaliculatum.

Aggregation of parasitoids and density‐independence of parasitism in field populations of the wasp Aphytis melinus and its host, the red scale Aonidiella aurantii

Suggestions based on some host‐parasitoid models, that aggregations of parasite attack in areas of high host density are necessary for effective biological control, are rejected and the model of Hassell (1982) seems to fit the data quite well.

Foraging for patchily-distributed hosts by the parasitoid, Nemeritis canescens

(1) The locomotory responses which influence patch time allocation were investigated for the parasitoid, Nemeritis canescens (Grav.). Arrestment in patches was brought about by orthokinetic and

The Natural Control of Population Balance in the Knapweed Gall-Fly (Urophora jaceana)

The population density of the gall-flies and its bearing on their fecundity and the effect of weather on the behaviour of thegall-flies are studied.