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opennotspecifiedMar 2021View details →

FIGURE 6 in Pseudopestalotiopsis gilvanii sp. nov. and Neopestalotiopsis formicarum leaves spot pathogens from guarana plant: a new threat to global tropical hosts

FIGURE 6. Leaf spot symptoms on tropical plants inoculated with Pseudopestalotiopsis gilvanii and Neopestalotiopsis formicarum, under greenhouse conditions. Presence of symptoms noticed on açaí palms (Euterpe oleraceae and E. precatoria), oil palm (Elaeis guineenses). Banana (Musa paradisiaca) displayed symptoms for N. formicarum but not for Ps. gilvanii. Absence of symptoms on rubber trees (Hevea brasiliensis). Uninoculated plants were employed as control.

opencc-zeroDec 2021View details →

Intraspecific interaction of host plants leads to concentrated distribution of a specialist herbivore through metabolic alterations in the leaves

1. Recent studies suggest that changes in leaf traits due to interactions between plants affect resource utilisation by and the distribution of herbivores. However, this has not yet been confirmed experimentally. Here, we investigated the effects of phenotypic plasticity in leaf traits of Rumex obtusifolius (host plant) in response to intra- and interspecific interaction on the distribution of two leaf beetles, Gastrophysa atrocyanea (specialist herbivore) and Galerucella grisescens (generalist herbivore). 2. We investigated the local population density of R. obtusifolius plants and the presence of leaf beetles on the plants at five study sites. Leaf chemicals (condensed tannins and total phenolics) were compared between aggregated and solitary R. obtusifolius plants. To clarify the effects of the interaction environment of R. obtusifolius plants on their leaf traits and on resource utilisation by the leaf beetles, we compared leaf chemicals and preferences of adult leaf beetles among treatments where R. obtusifolius experienced intraspecific interaction, interspecific interaction, or no interaction in cultivation experiments. Finally, we evaluated the independent and combined effects of patch size and intraspecific interaction on leaf beetle distribution in mesocosm experiments. 3. In the field, the presence of the specialist leaf beetle G. atrocyanea was positively correlated with the local population density (rosette overlap ratio) of R. obtusifolius plants; however, there was no correlation in the case of the generalist leaf beetle G. grisescens. In the cultivation experiments, plants in the intraspecific interaction treatment increased their leaf contents of condensed tannins and total phenolics, and G. atrocyanea consumed more of these leaves than leaves in other treatments. Similar results were observed in the field. In the mesocosm experiments, larger numbers of G. atrocyanea were distributed on R. obtusifolius plants exposed to below-ground intraspecific interaction than on plants not exposed to intraspecific interaction. 4. Our results provide experimental evidence that leaf-trait changes in response to intraspecific interaction between host plants influence specialist herbivore distribution. This highlights the need to integrate plant–plant interactions into our understanding of plant–animal interactions.

opencc-zeroDec 2021View details →

Complex adaptive architecture underlies adaptation to quantitative host resistance in a fungal plant pathogen

Plant pathogens often adapt to plant genetic resistance so characterization of the architecture underlying such an adaptation is required to understand the adaptive potential of pathogen populations. Erosion of banana quantitative resistance to a major leaf disease caused by polygenic adaptation of the causal agent, the fungus Pseudocercospora fijiensis, was recently identified in the northern Caribbean region. Genome scan and quantitative genetics approaches were combined to investigate the adaptive architecture underlying this adaptation. Thirty-two genomic regions showing host selection footprints were identified by pool sequencing of isolates collected from seven plantation pairs of two cultivars with different levels of quantitative resistance. Individual sequencing and phenotyping of isolates from one pair revealed significant and variable levels of correlation between haplotypes in 17 of these regions with a quantitative trait of pathogenicity (the diseased leaf area). The multilocus pattern of haplotypes detected in the 17 regions was found to be highly variable across all the population pairs studied. These results suggest complex adaptive architecture underlying plant pathogen adaptation to quantitative resistance with a polygenic basis, redundancy, and a low level of parallel evolution between pathogen populations. Candidate genes involved in quantitative pathogenicity and host adaptation of P. fijiensis were identified in genomic regions by combining annotation analysis with available biological data.

opencc-zeroDec 2020View details →

Sequestration of defenses against predators drives specialized host plant associations in preadapted milkweed bugs (Heteroptera: Lygaeinae)

Host plant specialization across herbivorous insects varies dramatically, but while the molecular mechanisms of host-plant adaptations are increasingly known, we often lack a comprehensive understanding of the selective forces that favor specialization. The milkweed bugs (Heteroptera: Lygaeinae) are engaged in ancestrally specialized associations with plants of the Apocynaceae from which they commonly sequester cardiac glycosides for defense, facilitated by resistant Na+/K+-ATPases and adaptations for transport, storage and discharge of toxins. Here, we show that three Lygaeinae species independently colonized four novel non-apocynaceous hosts that convergently produce cardiac glycosides. A fourth species shifted to a new source of toxins by tolerating and sequestering alkaloids from meadow saffron (Colchicum autumnale, Colchicaceae). Across three milkweed bug species tested, feeding on seeds containing toxins did not improve growth or speed of development, and even impaired growth and development in two species, but sequestration mediated protection of milkweed bugs against two natural predators: lacewing larvae and passerine birds. We conclude that physiological preadaptations and convergent phytochemistry facilitated novel specialized host associations. Since toxic seeds did not improve but either impaired growth or at most had neutral effects, selection by predators on sequestration of defenses, rather than the exploitation of additional profitable dietary resources, can lead to obligatory specialized host associations in otherwise generalist insects.

opencc-zeroJan 2022View details →

A specialist bee and its host plants experience phenological shifts at different rates in response to climate change

Changes in climate can alter the phenology of organisms, potentially decoupling partners within mutualisms. Previous studies have shown that plant and pollinator phenologies are shifting over time, but these shifts have primarily been documented for generalists and within small geographic regions, and the specific climatic cues regulating these shifts are not well-understood. We examined phenological shifts in a specialist pollinator and its host plant species over a 117-year study period using a digitized dataset of over 4,000 unique collection records. We assess how climatic cues regulate these organisms' phenologies using PRISM weather data associated with each record. We tested the hypothesis that rates of phenological change would be greater at northern latitudes. We found that the phenology of the specialist bee pollinator Habropoda laboriosa is changing over time, but at different rates across its range. Specifically, phenology is advancing to a greater degree in more northern populations, with increasing phenological advances of 0.04 days/year with each degree of latitude, and with a delay in phenology in more southern populations. In contrast, only one species in the host plant genus Vaccinium is experiencing phenological change over time. For this plant, rates of change are also variable across latitudes, but in a pattern opposite that of the bee; while phenology is advancing across its range, rates of advance are highest in more southern populations, with decreasing phenological advances of 0.01 days/year with each degree of latitude. The phenologies of both the bee and three of four Vaccinium spp. were regulated primarily by spring temperature, with phenologies overall advancing with increasing temperature, and with the strongest responses shown by the bee in northern populations. Our study provides partial support for the hypothesis that phenologies advance most at northern latitudes, but demonstrates that pollinators and plants do not adhere similarly to this prediction. Additionally, we illustrate the potential for phenological mismatch between a specialist pollinator and its host plants by showing that plants and pollinators are advancing their phenologies at different rates across space and time and with differing responses to changing climatic cues.

FIGURE 5 in Turrana ejuncida, a new species of Acanthocorini (Hemiptera: Heteroptera: Coreidae) from Cape Range, Western Australia, with discussion of its systematic position and host plant associations

FIGURE 5. Map of point localities of Turrana abnormis Distant (triangles) and T. ejuncida sp. nov. (circle). Localities of T. abnormis from Cassis & Gross (2002).

FIGURE 4 in Turrana ejuncida, a new species of Acanthocorini (Hemiptera: Heteroptera: Coreidae) from Cape Range, Western Australia, with discussion of its systematic position and host plant associations

FIGURE 4. Turrana ejuncida sp. nov. Micro-CT images of female terminalia (WAME106180). A) dorsal, B) ventral, and C) lateral views of tip of abdomen. Scale bar = 100 µm.

FIGURE 3 in Turrana ejuncida, a new species of Acanthocorini (Hemiptera: Heteroptera: Coreidae) from Cape Range, Western Australia, with discussion of its systematic position and host plant associations

FIGURE 3. Turrana ejuncida sp. nov. Micro-CT images of male genitalia (WAME106179). A) pygophore and semi-inflated aedeagus, lateral view; sclerotized portions of conjunctival processes coloured green. B) anterior of aedeagus. C) right paramere. Scale bars = 100 µm.

FIGURE 2 in Turrana ejuncida, a new species of Acanthocorini (Hemiptera: Heteroptera: Coreidae) from Cape Range, Western Australia, with discussion of its systematic position and host plant associations

FIGURE 2. Scanning electron micrographs of Turrana ejuncida sp. nov. female (WAME106180). A) head, lateral; B) head, dorsal; C) head and thorax, ventral; D) pronotum, dorsal; E) hemelytra, detail; F) metathoracic scent gland. Anterior to left in all images.

FIGURE 1 in Turrana ejuncida, a new species of Acanthocorini (Hemiptera: Heteroptera: Coreidae) from Cape Range, Western Australia, with discussion of its systematic position and host plant associations

FIGURE 1. Turrana ejuncida sp. nov. dorsal and lateral habitus images. A, B) holotype male (WAME106179); C, D) paratype female (WAME106180).

FIGURE 6 in Turrana ejuncida, a new species of Acanthocorini (Hemiptera: Heteroptera: Coreidae) from Cape Range, Western Australia, with discussion of its systematic position and host plant associations

FIGURE 6. Collecting sites of Turrana ejuncida sp. nov. in Cape Range National Park. A) flowering Ipomoea yardiensis (detail in inset) on remote rocky ridge adjacent to canyon. B) Triodia epactia (inset shows dry, brown underside of plant) at side of Charles Knife Canyon Road, on ridge.

opennotspecifiedFeb 2022View details →

FIGURE. Phylogenetic tree of specimens on Poaceae and related host plants constructed by MP method based on ITS+28S regions of rDNA. Bootstrap values of MP and ML are followed by the Bayesian posterior probabilities (Bpp) on the nodes in the topology. Asterisk () represents bootstrap values or Bpp less than 50% in the topology. Sample data are shown with voucher specimen number or GenBank accession number, and host plant. Sequence data determined in this study are shown in color. Teliospore shapes are shown in each clade detected, and new species are shown by asterisk () on clades. 0, I: Spermogonial and aecial host genus. Asterisk (*) on host plants: Spermogonial and aecial host plants. in Phylogenetic approach for identification and life cycles of Puccinia (Pucciniaceae) species on Poaceae from northeastern China

FIGURE. Phylogenetic tree of specimens on Poaceae and related host plants constructed by MP method based on ITS+28S regions of rDNA. Bootstrap values of MP and ML are followed by the Bayesian posterior probabilities (Bpp) on the nodes in the topology. Asterisk (*) represents bootstrap values or Bpp less than 50% in the topology. Sample data are shown with voucher specimen number or GenBank accession number, and host plant. Sequence data determined in this study are shown in color. Teliospore shapes are shown in each clade detected, and new species are shown by asterisk (*) on clades. 0, I: Spermogonial and aecial host genus. Asterisk (*) on host plants: Spermogonial and aecial host plants.

opencc-zeroMar 2022View details →

Larval parasitism in a specialist herbivore is explained by phenological synchrony and host plant availability

Parasitism is a key factor in the population dynamics of many herbivorous insects, although its impact on host populations varies widely, for instance, along latitudinal and altitudinal gradients. Understanding the sources of geographical variation in host-parasitoid interactions is crucial for reliably predicting the future success of the interacting species under a context of global change. Here, we examine larval parasitism in the butterfly Aglais urticae in south-west Europe, where it is a mountain specialist. Larval nests were sampled over two years along altitudinal gradients in three Iberian mountain ranges, including the Sierra Nevada, home to its southernmost European population. Additional data on nettle condition and adult butterflies were obtained in the study areas. These data sources were used to investigate whether or not differences in parasitism rates are related to the geographical position and phenology of the host, and to the availability of the host plants. Phenological differences in the host populations between regions were related to the severity of summer drought and the corresponding differences in host plant availability. At the trailing-edge of its distribution, the butterfly's breeding season was restricted to the end of winter and spring, while in its northern Iberian range the season was prolonged until mid-summer. Although parasitism was an important source of mortality in all regions, parasitism rates and parasitoid richness were highest in the north and lowest in the south. Moreover, within a region, there was a notable increase in parasitism rates over time, which probably led to selection against an additional late-summer host generation in northern regions. Conversely, the shorter breeding season in Sierra Nevada resulted in a loss of synchrony between the host and one important late-season parasitoid, Sturmia bella, which may partly explain the high density of this butterfly species at the trailing-edge of its range. Our results support the key role of host phenology in accounting for differences in parasitism rates between populations. They also provide insights into how climate through host plant availability affects host phenology and, ultimately, the impact of parasitism on host populations.

opencc-zeroMar 2022View details →

Tri-trophic interactions with avian predators: the effect of host plant species and herbivore-induced plant volatiles on recruiting avian predators

<div> Herbivore-induced plant volatiles (HIPVs) are important signaling compounds released by plants upon wounding. These compounds have been shown to mediate tri-trophic interactions in recruiting insect predators and parasitoids. Recent work has begun to show that avian species, which were once thought to have a very limited sense of smell, can cue in on these HIPVs to find insect prey. Here, we test the ability for two general HIPVs, methyl jasmonate and methyl salicylate, to recruit avian predators. We test the recruitment efficacies of these HIPVs across 4 different host plant species (black walnut, red maple, cattail, and wheat) and use clay caterpillars to quantify predation by insectivorous birds. We found no significant differences in predation between treatment groups across any of our host plants. However, there was a nearly-significant effect of methyl salicylate in black-walnut trees. Interestingly, our results did show a significant effect of host plant species on predation levels. The two tree species, particularly black walnut, had higher levels of predation than the herbaceous species. We discuss the implications of these results and suggest a number of ideas and suggestions for future studies investigating the role of HIPVs in attracting insectivorous birds. </div>

FIGURE 7 in Immature stages and new host plant records for four satyrine species feeding on herbaceous bamboos in southeastern Peru (Lepidoptera: Nymphalidae: Satyrinae: Satyrini)

FIGURE 7. Immature stages with some notable characters indicated with arrows, Nhambikuara mima compared to Splendeuptychia furina; Paryphthimoides brixius compared to Paryphthimoides terrestris: 1a, b) Paryphthimoides brixius ultimate instar in dorsal view and lateral view; 2a, b) Paryphthimoides terrestris ultimate instar in dorsal view and lateral view; 3a, b) Nhambikuara mima ultimate instar in dorsal view and lateral view; 4a, b) Splendeuptychia furina ultimate instar prior to pupation in dorsal view and lateral view. 1c, 2c) Paryphthimoides brixius ultimate instar head capsule and Paryphthimoides terrestris ultimate instar head capsule; 3c, 4c) Nhambikuara mima ultimate instar head capsule and Splendeuptychia furina ultimate instar head capsule; 1d–f, 2d, e) pupa of Paryphthimoides brixius and Paryphthimoides terrestris; 3d–f, 4d, e) pupa of Nhambikuara mima compared to Splendeuptychia furina. All images for Nhambikuara mima, Splendeuptychia furina, and Paryphthimoides brixius are reproduced from the present article; All images for Paryphthimoides terrestris from Corahua-Espinioza et al. (in press).

FIGURE 6 in Immature stages and new host plant records for four satyrine species feeding on herbaceous bamboos in southeastern Peru (Lepidoptera: Nymphalidae: Satyrinae: Satyrini)

FIGURE 6. Host plants for Magneuptychia harpyia: Olyra latifolia L.: 1a) leaves; 1b) close-up view of the nodes; 1c) close-up view of inflorescence materials; 1d) host plant in situ. 1e) Taquara micrantha in situ 2a, b) adult of Magneuptychia harpyia in dorsal and ventral view (based on 2021-FLP-IMM-0352).

FIGURE 4 in Immature stages and new host plant records for four satyrine species feeding on herbaceous bamboos in southeastern Peru (Lepidoptera: Nymphalidae: Satyrinae: Satyrini)

FIGURE 4. Host plant, two variations of Taquara micrantha. Taquara micrantha with pubescence on the abaxial surface as a host plant for Nhambikuara mima and Paryphthimoides brixius: 1a) leaves; 1b) close-up view of the node and abaxial part showing pubescence; 1c) inflorescence materials; 1d) host plant in situ. Taquara micrantha lacking pubescence for Splendeuptychia furina: 2a) leaves and inflorescence in situ; 2b) close-up view of nodes; 2c) close-up view of abaxial surface showing lack of pubescence; 2d) host plant in situ.

FIGURE 5 in Immature stages and new host plant records for four satyrine species feeding on herbaceous bamboos in southeastern Peru (Lepidoptera: Nymphalidae: Satyrinae: Satyrini)

FIGURE 5. Illustrations of head capsules: a, b, c) first, second, and fifth (ultimate) instar of Nhambikuara mima, in frontal view; d) fifth (ultimate) instar of N. mima, lateral view indicating labeled chalazae; e–h) first, second, fourth and fifth instar of Splendeuptychia furina, in frontal view; i, j) third and fifth (ultimate) instar of Paryphthimoides brixius, in frontal view. Figure a, b are based on 2021-FLP-IMM-0538; c, d are based on 2021-FLP-IMM-0489; e, f, g are based on 2021-FLP-IMM-0554; h are based on 2021-FLP-IMM-0316; i, j are based on 2021-FLP-IMM-0395.

FIGURE 3 in Immature stages and new host plant records for four satyrine species feeding on herbaceous bamboos in southeastern Peru (Lepidoptera: Nymphalidae: Satyrinae: Satyrini)

FIGURE 3. Life history of Paryphthimoides brixius: 1a, b) third instar in dorsal and lateral view; 2a, b) fourth instar in dorsal and lateral view; 3a, b) fifth (ultimate) instar in dorsal and lateral view; 4a, b, c) pupa in dorsal, lateral and ventral view; 5a, b) adult in dorsal and ventral view. All illustrations based on 2021-FLP-IMM-0395.

FIGURE 2 in Immature stages and new host plant records for four satyrine species feeding on herbaceous bamboos in southeastern Peru (Lepidoptera: Nymphalidae: Satyrinae: Satyrini)

FIGURE 2. Life history of Splendeuptychia furina: 1a) egg with brown stripes and mandibles showing through translucence, 1b) head capsule showing through translucence two days prior to hatching; 2a, b) first instar in dorsal and lateral view; 3a, b) second instar in dorsal and lateral view; 4a, b) third instar in dorsal and lateral view; 5a, b) fourth instar in dorsal and lateral view; 6a, b) fifth (ultimate) instar in dorsal and lateral view; 7a, b) ultimate instar exhibiting purple colouration a day prior to pupation, dorsal and lateral view; 8a, b, c) pupa in dorsal, lateral and ventral view; 9a, b) adult in dorsal and ventral view. Figure 2b, 3b are based on 2021-FLP-IMM-0556; otherwise illustrations based on 2021-FLP-IMM-0554.