Insect Richness Research Articles

16S rRNA Gene Sequencing Reveals Specific Gut Microbes Common to Medicinal Insects.

Insects have a long history of being used in medicine, with clear primary and secondary functions and less side effects, and the study and exploitation of medicinal insects have received increasing attention. Insects gut microbiota and their metabolites play an important role in protecting the hosts from other potentially harmful microbes, providing nutrients, promoting digestion and degradation, and regulating growth and metabolism of the hosts. However, there are still few studies linking the medicinal values of insects with their gut microbes. In this study, we focused on the specific gut microbiota common to medicinal insects, hoping to trace the potential connection between medicinal values and gut microbes of medicinal insects. Based on 16S rRNA gene sequencing data, we compared the gut microbiota of medicinal insects [Periplaneta americana, Protaetia (Liocola) brevitarsis (Lewis) and Musca domestica], in their medicinal stages, and non-medicinal insects (Hermetia illucens L., Tenebrio molitor, and Drosophila melanogaster), and found that the intestinal microbial richness of medicinal insects was higher, and there were significant differences in the microbial community structure between the two groups. We established a model using a random-forest method to preliminarily screen out several types of gut microbiota common to medicinal insects that may play medicinal values: Parabacteroides goldsteinii, Lactobacillus dextrinicus, Bifidobacterium longum subsp. infantis (B. infantis), and Vagococcus carniphilus. In particular, P. goldsteinii and B. infantis were most probably involved in the anti-inflammatory effects of medicinal insects. Our results revealed an association between medicinal insects and their gut microbes, providing new development directions and possibly potential tools for utilizing microbes to enhance the medicinal efficacy of medicinal insects.

Insect diversity and succession patterns on pig cadavers in Changwon, South Korea

AbstractSuccession patterns spanning three seasons for insect fauna on pig cadavers were studied in Changwon, South Korea in 2018 and 2019. A total of 107 species belonging to 41 families in six orders were collected and identified. Four decomposition stages were recognized: fresh, bloated, decay, and dry. The number of species increased significantly after the fresh stage and reached the maximum number by the decay stage. The sequence of insect succession followed a general pattern in which Diptera peaked initially and Coleoptera peaked later.Chrysomya pinguiswas the most frequently present species, and the timing of its different developmental stages on cadavers could be the most important indicator for post‐mortem interval estimations in Changwon. Spatial and seasonal differences in the richness of insects were not significant. However,Calliphora nigribarbisoccurred exclusively in spring and autumn, andPheropsophus javanusoccurred exclusively in one locality. Therefore, these species may be important for characterizing the different seasons or locations during post‐mortem interval estimations. A list of the insects associated with above‐ground pig cadavers during the three seasons was compiled, and it may be useful for estimating the time since death in areas with a similar bioclimate.

A preliminary survey on litter insect’s diversity through pitfall trap in different ecosystems of south 24 Parganas district, West Bengal, India

The present paper documents/discuss the preliminary study on litter insect abundance and diversity of insect species in diversity through pitfall trap in different ecosystems of South 24 Parganas District conducted during November, 2021- March, 2022. A total of 905 insects from 8 orders, 25 families were recorded. This study shows that Hymenoptera (44%) was the most dominant order according to total number of individuals, followed by Coleoptera (26%), Diptera (17%), Hemiptera (5%), Collembola (4%), Orthoptera (2%), Isoptera (1%) and Dictyoptera (1%). The present study was also conducted to determine the abundance of insects species; species richness, dominance and evenness of insect fauna from different ecosystems. The Simpson’s Index diversity is highest in Guava Orchard (0.345) and lowest in Medicinal Plants’ Garden (0.281). The species richness, evenness and diversity of insects were calculated by Margalef’s Index, Pielou’s Index and Shannon-Wiener Index respectively.

Plant Diversity Is More Important than Climate Factors in Driving Insect Richness Pattern along a Latitudinal Gradient

The insect data of 93 national nature reserves in China was used to identify the underlying drivers’ potential for species richness along geographical gradients. We assessed the correlations between predictors (climate and soil) and response variables (insect richness). We found that the following: insect diversity decreased significantly at higher latitudes. The latitudinal variation in insect richness seems to be driven by climate and soil variations and also the diversity of other biota. Among all the tested predictors, plant diversity explained the most latitudinal patterns of insect richness (R2 = 0.498). Insect richness showed a positive correlation with the diversity of other biota and climate factors (mean annual temperature and mean annual precipitation) and was negatively associated with soil pH. Overall, the interspecific relationship between organisms was the main driver of insect diversity’s latitudinal pattern. However, the effects of climate and soil factors cannot be ignored.

Evaluation of flower visiting insects specimen sampling methodology in turfgrass–forb habitat

AbstractPollination is fundamental to healthy ecosystems, and global pollination services have been valued at over $200 billion annually. However, landscape fragmentation, urban growth, and ecosystem degradation adversely influence insect pollinator biodiversity. Efforts to mitigate these factors must be enhanced in order to establish and increase pollinator populations. As such, a better understanding of the landscapes that make up their habitats may help mitigate these negative effects. Gauging the effect of landscapes on pollinators requires identification of insect richness and abundance, but studies that evaluate trapping and netting methodology over established turfgrass–forb habitat are scant. Here, we present preliminary findings from a single location (Starkville, MS) regarding the effectiveness of two sampling methodologies, netting, and pan traps. Methods were compared over bermudagrass (Cynodon dactylon) mixed with white clover (Trifolium repens). The total abundance, taxa abundance, and the link between insect taxa and method were examined. Netting was found to be more effective at catching pollinators, especially those belonging to the Apidae and Syrphidae families. Apidae and Syrphidae were the most abundant families present. Halictidae showed higher abundance in pan traps, however, no significant difference in abundance was found between it and other families. Ongoing work seeks to identify all samples to species level. The work presented here has been replicated at another site and will be combined with this study to enable broader inferences.

Diversified and monoculture, contrasts in some parasitoids community of coffee crop / Monocultura diversificada e monocultura, contrastes em alguns parasitóides da comunidade da cultura do café

The diversification of the agriculture is a practice that is getting focus in the last decade, but it always was the natural way. The diversification, being anthropomorphic or natural, brings benefits to the crop, farmer, and the environment. One way possible to restore the diversity of the crop, is planting trees along the culture. Doing this, we can restore the diversification and help to improve ecological function, as pest control. This work was conducted at Fazenda da Lagoa, Santo Antonio do Amparo municipality, Brazil in a coffee plantation diversified with different tree species, being them Avocado, Macadamia, Mangium, Teak and Red Cedar. The insects were collected utilizing yellow plastic pan traps left in the field for a 48h period. Each tree species was sampled separated and a monoculture coffee as control. We found 254 insects in 40 species being 22 species of Braconidae, six species of Eulophidae and 12 Mymaridae species. Our results showed that all tree species had a greater insect richness than Monoculture coffee with Avocado (16), Mangium (18), Cedar (16), Macadamia (19), Teak (16) and Full Sun (10), also we found more abundance of parasitoids at the diversified coffee than in monoculture.

Recent trends in stream macroinvertebrates: warm-adapted and pesticide-tolerant taxa increase in richness

Recently, a plethora of studies reporting insect declines has been published. Even though the common theme is decreasing insect richness, positive trends have also been documented. Here, we analysed nationwide, systematic monitoring data on aquatic insect richness collected at 438 sites in Switzerland from 2010 to 2019. In addition to taxonomic richness, we grouped taxa in accordance with their ecological preferences and functional traits to gain a better understanding of trends and possible underlying mechanisms. We found that in general, richness of aquatic insects remained stable or increased with time. Warm-adapted taxa, common feeding guilds and pesticide-tolerant taxa showed increasing patterns while cold-adapted, rarer feeding guilds and pesticide-sensitive taxa displayed stable trends. Both climate and land-use-related factors were the most important explanatory variables for the patterns of aquatic insect richness. Although our data cover the last decade only, our results suggest that recent developments in insect richness are context-dependent and affect functional groups differently. However, longer investigations and a good understanding of the baseline are important to reveal if the increase in temperature- and pesticide-tolerant species will lead to a decrease in specialized species and a homogenization of biotic communities in the long term.

Effects of urbanization on Odonata assemblages in tropical island streams in San Juan, Puerto Rico

Urbanization has considerable impacts on stream ecosystems. Streams in urban settings are affected by multiple stressors such as flow modifications and loss of riparian vegetation. The richness and abundance of aquatic insects, such as odonates, directly reflect these alterations and can be used to assess urban impacts on streams. The effects of urbanization on odonate richness and abundance on tropical islands is as yet poorly understood. The objective of this study is to identify the effects of urbanization on stream habitat quality and associated odonate assemblages in Puerto Rico. We sampled 16 streams along a rural to urban gradient in the San Juan Metropolitan Area, where each stream was characterized using the Stream Visual Assessment Protocol (SVAP) for Puerto Rico and by analyzing their surrounding land cover. A 100-m segment of each stream was surveyed to assess adult odonate richness and abundance during the rainy and dry seasons. Adults were identified visually, and their abundance was recorded. Favorable local scale factors, like improved habitat quality, as measured with the SVAP, resulted in higher abundances of odonates. However, regional factors such as percent urban cover did not appear to significantly affect richness and abundances of odonates. Overall, our study indicates that odonate assemblages are affected by the loss of habitat integrity, and conservation of tropical odonates may benefit from focusing on local scale factors.

Seed treatments containing neonicotinoids and fungicides reduce aquatic insectrichness and abundance in midwestern USA-managed floodplain wetlands.

Agrochemicals including neonicotinoid insecticides and fungicides are frequently applied as seed treatments on corn, soybeans, and other common row crops. Crops grown from pesticide-treated seed are often directly planted in managed floodplain wetlands and used as a soil disturbance or food resource for wildlife. We quantified invertebrate communities within mid-latitude floodplain wetlands and assessed their response to use of pesticide-treated seeds within the floodplain. We collected and tested aqueous and sediment samples for pesticides in addition to sampling aquatic invertebrates from 22 paired wetlands. Samples were collected twice in 2016 (spring [pre-water level drawdown] and autumn [post-water level flood-up]) followed by a third sampling period (spring 2017). Meanwhile, during the summer of 2016, a portion of study wetlands were planted with either pesticide-treated or untreated corn seed. Neonicotinoid toxic equivalencies (NI-EQs) for sediment (X̅ = 0.58μg/kg), water (X̅ = 0.02μg/L), and sediment fungicide concentrations (X̅ = 0.10μg/kg) were used to assess potential effects on wetland invertebrates. An overall decrease in aquatic insect richness and abundance was associated with greater NI-EQs in wetland water and sediments, as well as with sediment fungicide concentration. Post-treatment, treated wetlands displayed a decrease in insect taxa-richness and abundance before recovering by the spring of 2017. Information on timing and magnitude of aquatic insect declines will be useful when considering the use of seed treatments for wildlife management. More broadly, this study brings attention to how agriculture is used in wetland management and conservation planning.

Major land use and vegetation influences on potential pollinator communities in the High Plains of Texas

In 2016, the annual value of all global crops dependent upon pollination was valued at $ 235–$ 577 billion (US$). Pollination service is threatened by habitat loss, pesticides, and climate change. We collected potential pollinators with blue vane traps in native grasslands, Conservation Reserve Program (CRP) lands, and cropland (land use), and their embedded playa wetlands (land type) in the Southern High Plains of Texas (SHP). We collected vegetation data that included floral cover, floral diversity, native grass cover, introduced grass cover, canopy gap, and duff cover. Our objective was to determine if individual vegetation characteristics influenced potential pollinator abundance and richness in addition to land use or land type as a whole. The top model explaining abundance was land use, land type, and floral cover. Floral cover had a positive influence on all land uses. The top model that explained insect richness was land use x floral cover, land type, canopy gap, and duff cover. Floral cover positively influenced insect richness in native grasslands but negatively influenced cropland and CRP richness. Percent of canopy gap had a slight negative influence on insect richness, and duff cover positively influenced richness. Our recommendations to land managers are to protect playas to preserve undisturbed areas and native floral resources and seed all future CRP contracts with floral rich plantings to provide for pollinators over the entire growing season.Implications for insect conservationOur results show that vegetation characteristics shared by all land uses such as floral cover, canopy gap and duff cover influence pollinator abundance and richness. Therefore, conserving playa wetlands and programs such as the CRP have the potential for enhancing pollinator habitat in working landscapes of the SHP of Texas.

Vertical stratification of insect abundance and species richness in an Amazonian tropical forest

Tropical forests are among the most biodiverse biomes on the planet. Nevertheless, quantifying the abundance and species richness within megadiverse groups is a significant challenge. We designed a study to address this challenge by documenting the variability of the insect fauna across a vertical canopy gradient in a Central Amazonian tropical forest. Insects were sampled over two weeks using 6-m Gressitt-style Malaise traps set at five heights (0 m–32 m–8 m intervals) on a metal tower in a tropical forest north of Manaus, Brazil. The traps contained 37,778 specimens of 18 orders of insects. Using simulation approaches and nonparametric analyses, we interpreted the abundance and richness of insects along this gradient. Diptera, Hymenoptera, and Coleoptera had their greatest abundance at the ground level, whereas Lepidoptera and Hemiptera were more abundant in the upper levels of the canopy. We identified species of 38 of the 56 families of Diptera, finding that 527 out of 856 species (61.6%) were not sampled at the ground level. Mycetophilidae, Tipulidae, and Phoridae were significantly more diverse and/or abundant at the ground level, while Tachinidae, Dolichopodidae, and Lauxaniidae were more diverse or abundant at upper levels. Our study suggests the need for a careful discussion of strategies of tropical forest conservation based on a much more complete understanding of the three-dimensional distribution of its insect diversity.

Climate-induced forest dieback drives compositional changes in insect communities that are more pronounced for rare species

Species richness, abundance and biomass of insects have recently undergone marked declines in Europe. We metabarcoded 211 Malaise-trap samples to investigate whether drought-induced forest dieback and subsequent salvage logging had an impact on ca. 3000 species of flying insects in silver fir Pyrenean forests. While forest dieback had no measurable impact on species richness, there were significant changes in community composition that were consistent with those observed during natural forest succession. Importantly, most observed changes were driven by rare species. Variation was explained primarily by canopy openness at the local scale, and the tree-related microhabitat diversity and deadwood amount at landscape scales. The levels of salvage logging in our study did not explain compositional changes. We conclude that forest dieback drives changes in species assemblages that mimic natural forest succession, and markedly increases the risk of catastrophic loss of rare species through homogenization of environmental conditions.

Inventory of insects in the El Ghrous's palm grove (Biskra; Algeria)

The diversity and species richness of insects were studied at the palm grove of El Ghrous. The insects were collected using two types of traps: Barber and Aerial. Forty-four insect species were inventoried. This inventory shows a predominance of Order Coleoptera with 6 families, 13 species and 241 individuals, followed by Hemiptera with 5 families, 7 species and 111 individuals, and Orthoptera with 2 families, 7 species and 54 individuals. J. Biodivers. Conserv. Bioresour. Manag. 2021, 7(1): 85-94

Degradative succession of the insects in small rodents in subtropical systems

We evaluated the insect succession in small rodent carcasses on the soil extracts (surface vs. buried) in two areas (riparian vs. agricultural) and two seasonal periods (spring vs. summer). Daily, the rodent carcasses were weighed and the insects present were collected in them for counting and family level identification. We also measured the air and soil temperature daily, in addition to the physical and chemical characteristics of the soil. The total of 11,059 individuals from 28 taxa was collected. The most abundant taxa were Calliphoridae (70%), Formicidae (20%), Muscidae (2%), and Sarcophagidae (2%). Insect richness was higher in spring in riparian vegetation areas; however, decomposition and insect abundance were greater in spring in agricultural areas by the high temperature measured. Vespidae, Sarcophagidae, Muscidae, and Calliphoridae decreased over time with abundance peaks respectively at 3, 7, 7, and 8 days in riparian vegetation areas. Calliphoridae decreased abundance over time with a peak at five days, but Armadillidiidae increased with peak at 6-9 days in agricultural areas. Decay and insect abundance was high in agricultural areas, mainly on the soil surface. Insect richness was high in riparian vegetation areas, especially on the soil surface. Only the superficial layers of soil presented taxon indicators and all decreased over time with abundance peaks of Calliphoridae, Sarcophagidae, and Muscidae at 5-8, 7, and 7 days, respectively. This abundance peak of insect families help to understand the degradative succession of the insect community in small rodents in subtropical systems of the neotropical region.

Variations in chemical defences and patterns of natural enemy attack between native and introduced populations of fireweed (Senecio madagascariensis): Implications for biological control

AbstractNative to South Africa, fireweed (Senecio madagascariensis Poiret; Asteraceae) is an annual or short‐lived perennial herb that is highly invasive in Australia, where it is a target for biological control. Preliminary research indicates that fireweed may be undergoing adaptive changes along its invasion gradient in Australia. Changes, such as a shift in plant chemical defence, may influence fireweed’s interaction with specialist insect herbivores, and hence the efficacy of a biocontrol program. As the testing of biocontrol candidates is a rigorous and lengthy process, confirmation of fireweed’s susceptibility to insect attack may assist in fast tracking candidate suitability, where changes in plant defensive chemistry are found. In a large experimental field study in fireweed’s native range, we compared the susceptibility of Australian and South African populations to insect natural enemy attack (in terms of plant biomass, insect richness and composition). Simultaneously, we assessed the variation in plant pyrrolizidine alkaloid concentrations and composition to rationalise any differences in natural enemy attack between populations. We found no significant differences in plant biomass across fireweed populations, despite significantly higher alkaloid concentrations in Australian populations. The composition of the endophagous (specialist) insect herbivore assemblage was related to alkaloid composition, but there were only minor differences in the assemblage between Australian and South African fireweed populations. Moreover, we found no significant differences in the abundance, richness or Shannon diversity indices of endophagous or ectophagous (generalist) insect herbivores between Australian and South African fireweed populations. Our results suggest that despite variations in chemical defence, Australian fireweed populations displayed neither reduced nor increased susceptibility to specialist insect herbivore attack, supporting the notion that if host‐specific biocontrol agents are released, their impact in Australia is unlikely to be influenced by any changes in plant chemical defence.

Fire affects galling insect communities through vegetation changes in a subtropical seasonally semiarid forest

Abstract Fire is one of the main factors shaping vegetation characteristics around the world, with deep and complex effects on higher levels of the food web and ecosystem functioning. Specialist insects tend to be more vulnerable to fire than generalists due to their higher dependency on host plants; however, fire effects on specialist insects are still not clearly known. Our aim was to understand how fire‐induced changes in plant richness and floristic composition modulate community features of galling insects under different fire scenarios. Specifically, we address the following questions: Are changes in galling insect richness and herbivory explained by the variation in plant richness and floristic composition under different fire scenarios? Are species composition of vegetation and galling insect communities coupled under different fire scenarios? Species richness of plant and galling insect communities was higher in burned than in unburned plots, but the highest species richness was observed under different fire scenarios in both communities. Galling insect richness was better predicted by floristic composition than plant richness. Herbivory was similar under different fire scenarios and weakly related to plant richness and composition. Species composition of vegetation and galling insect communities was strongly coupled across different fire scenarios. The characteristics of galling insect communities were strongly affected by fire through vegetation changes, and were better explained by floristic composition than by plant richness. Our results highlight the importance of selecting areas under different fire scenarios to maximise biodiversity conservation.

Effects of adjacent habitat on nocturnal flying insects in vineyards and implications for bat foraging

Bat populations are threatened in many regions of the world, partly due to the loss of foraging and commuting habitats in farmland and declines in insect prey populations caused by agricultural intensification. Given that bats play an important role as bioindicators and in suppressing crop pests, it is crucial to mitigate negative impacts that arise from these threats. In this study we evaluated the richness, quantified at family level, and abundance of bat prey insects in organic vineyards surrounded by three types of adjacent habitat: urban/semi-urban areas, exotic tree plantations, and remnants of native vegetation. The relationship between the abundance of prey and the foraging activity of bats in the vineyards was also examined. Insects were sampled using ultraviolet light traps, located both inside and at the edge of the vineyards. Bat activity was monitored at each site using acoustic recorders. The insect richness was unaffected by the type of adjacent habitat and did not differ between the edge and the interior of the vineyards. In contrast, insect abundance was significantly influenced by the type of adjacent habitat. Vineyards adjacent to native vegetation and exotic tree plantations showed the highest abundances for most insect orders present in the bat diet compared to urban areas. Bat activity was significantly correlated with the abundance of Coleoptera and Lepidoptera, with mixed effects between bat species (negative for Tadarida brasiliensis, positive for Lasiurus varius, Lasiurus villosissimus and Myotis chiloensis). Crop edges adjacent to native vegetation provides important foraging habitat for bats and should therefore be considered in agricultural management. Locating vineyards close to these habitats may promote bat conservation via increased prey insects and may also benefit winegrowers through the ecosystem services provided by insectivorous bats in this crop.

Insects and their Laboulbeniales (Ascomycota, Fungi) of Lake Eustis and Emeralda Marsh Conservation Area: A case study on urbanization and diversity.

A rapid biodiversity assessment of insects and associated Laboulbeniales fungi was conducted over the course of five nights in August, 2018, at two central Florida lakes: Lake Eustis and the nearby protected and restored National Natural Landmark, Emeralda Marsh Conservation Area (EMCA), which encompasses a portion of Lake Griffin. Lake Eustis was surveyed for Laboulbeniales in 1897 by mycologist Dr. Roland Thaxter but has not since been investigated. Because Lake Eustis has been urbanized, with the lake perimeter almost entirely altered by human development, the site offers a look into Laboulbeniales diversity across a 121‐year timeline, before and after human development. By surveying Lake Eustis and EMCA, a modern case study comparison of Laboulbeniales and insect diversity between a developed and a protected and restored system is made. A total of 4022 insects were collected during the rapid assessment. Overall, insect abundance was greater at EMCA, with 3001 insects collected, than 1021 insects collected from Eustis. Although family‐level insect richness was comparable between sites, with 55 families present at EMCA and 56 at Eustis, 529 out of 3001 (17.6%) of the insects collected at EMCA were hosts to parasitic Laboulbeniales fungi, whereas only 2 out of 1021 (0.19%) collected from Eustis were infected. A total of 16 species of Laboulbeniales found at EMCA compared with only one at Eustis. The current number of Laboulbeniales species documented at Eustis was incredibly depauperate compared with the 26 species and two varieties recorded by Thaxter in 1897. These findings suggest the possibility of utilizing Laboulbeniales as indicators of ecosystem health, and future research should investigate this question further. A figure displaying host–parasite records and a species list of Laboulbeniales are presented. Finally, updated occurrence records for species of Ceratomyces and Hydrophilomyces are provided.

The responses of different insect guilds to grassland degradation in northeastern China

Grassland insect diversity in many parts of the world is severely threatened by recent deterioration caused by global change and human activities. Insect species richness and abundance are likely sensitive to grassland degradation because of changes in vegetation structure and microclimates, and yet, our understanding of how diversity of insect community, particularly insect guilds responds to grassland degradation is still limited. Here, we conducted a field experiment to examine the responses of richness and abundance of total insects and different insect guilds along degraded levels (i.e., non-degraded, moderately, and severely degraded site) in meadow steppe at northeastern China. We found that higher species richness of total insects was detected in the moderately degraded sites, and there was no difference in abundance between the three sites. Furthermore, the responses of richness and abundance of each insect guild were significantly different. Hemiptera richness was significantly higher at moderately degraded sites, and Orthoptera richness was higher in severely degraded sites. Abundance of Hemiptera and Orthoptera increased with the increasing levels of degraded grasslands, but the abundance of Hymenoptera and Coleoptera decreased. Moreover, effect size of grassland degradation on Orthoptera abundance was larger from non-degraded to moderately degraded grassland; and larger effect size on Coleoptera abundance from moderately to severely degraded grassland. The different responses of insect guilds to grassland degradation are mainly attributed to changes in food and microclimate availability. In the light of convenience and operability, the finding from the study suggested that the abundance of an insect guild, rather than total insects and insect diversity seem to be a useful ecological indicator when assessing the levels of grassland degradation.

Soils and seasonality influence the richness of gall-inducing insects and their host plants in a tropical dry forest

The richness of specialized herbivores and their host plants in a Brazilian dry forest was inventoried to evaluate if soil types and seasonality are important factors determining the composition of gall-inducing insects and their host plants in Caatinga environments on a local scale. This study recorded 12 different morphotypes of gall distributed among eight host species belonging to five botanical families. Both soils and seasonality influenced the number of species and individuals of host plant, and the richness of gall-inducing insect. The greatest richness of gall-inducing insects and their host plants was observed during the rainy season in the Caatinga vegetation on soils of sedimentary origin, which is considered to have low fertility as regards phosphorus content. Our results corroborate the hypothesis of soil fertility which predicts that the richness of gall-inducing insects will be higher on infertile soils and demonstrate the importance of substrate and seasonality for the richness of gall-inducing insects in Caatinga on a local scale.