Differences in Foliage Affect Performance of the Lappet Moth,Streblote panda: Implications for Species Fitness

Gonzalo-Calvo, David de; Molina, José María

doi:10.1673/031.010.14137

“…Defences induced by gypsy moths include compounds such as phenolic glycosides and hydrolysable tannins that reduce the digestibility of foliage (Wold & Marquis, ; Redman & Scriber, ; Kosola et al, ). The consumption of both damaged and regrown foliage can adversely affect the growth and survival of herbivores (Redman & Scriber, ; Calvo & Molina, ). Additional indirect effects of gypsy moth outbreaks on native Lepidoptera include increased densities of generalist parasitoid species introduced to control the gypsy moth, such as Compsilua concinnata M. and other tachinids, which have been found to kill over 200 species of native Lepidoptera (Howarth, ; Wagner & Van Driesche, ).…”

Section: Introductionmentioning

confidence: 99%

Lepidoptera-specific insecticide used to suppress gypsy moth outbreaks may benefit non-target forest Lepidoptera

Manderino¹,

Crist

²

,

Haynes³

2014

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1 Despite considerable interest in the impacts of forest-defoliating insects and pesticide-based suppression of defoliator outbreaks on non-target arthropods, studies have often been hampered by the unpredictability of outbreaks. 2 We evaluated the long-term impacts of forest defoliation by gypsy moths, and the suppression of their outbreaks with Bacillus thuringiensis var. kurstaki (Btk), on native moths. Three years after a gypsy moth outbreak, moth diversity and abundance were compared among sites that were defoliated but not sprayed with Btk (defoliated sites), defoliated and sprayed (Btk sites) or neither (undisturbed sites). We conducted separate evaluations of the effects of disturbance history on the overall moth community, taxonomic subgroups (families) and moths differing in their dietary overlap with gypsy moths. 3 Analyses of the full moth community revealed no effects of disturbance history on local ( ) moth diversity or diversity of moths among sites ( -diversity). The -or -diversities of moths classified by their dietary overlap with gypsy moths (overlapping, partially overlapping, not overlapping) were also not affected by disturbance history. However, taxonomic affiliation was important. Geometridae -diversity in late summer was significantly lower in defoliated sites than in Btk or undisturbed sites. No effects of disturbance history on moth abundances were found. 4 We conclude gypsy moth defoliation had negative effects on a major moth family (Geometridae), although Btk application may have protected Geometridae from the adverse effects of gypsy moth defoliation. The results of the present study help to clarify the relative, and sometimes countervailing, effects of defoliators and microbial pesticides on forest communities.

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“…In order to grow and reproduce, herbivorous insects must acquire nutrients, and therefore make host selection decisions based upon the nutrient content of their food (Behmer 2009). A diet of poor quality food can lead to impaired development and survival of insect herbivores (Calvo and Molina 2010). Therefore, a correlation between reduced insect abundance, or reduced damage, with leaf colour may be the result of interactions between plant nutritional status and insect nutritional requirements.…”

Section: Post-contact Correlated Cues -Leaf Nutrientsmentioning

confidence: 99%

Do foliar anthocyanin pigments in horopito (Pseudowintera colorata) function as visual signals to deter insect herbivores?

Menzies¹

2

0

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Anthocyanin pigments are synthesised in the leaves of many plants, however the adaptive significance of these pigments is not entirely understood. It has been postulated that their red colours may function as visual signals through coevolution between herbivorous insects and their host tree species, though the hypothesis lacks solid empirical evidence. I investigated the leaf signalling hypothesis using Pseudowintera colorata, focusing on five areas: 1) I exploited the natural polymorphism in leaf colour of P. colorata to test the predictions that (i) bright leaf colour is a reliable signal of a plant’s defensive commitment; (ii) insects in the field avoid trees that are brightly coloured; and (iii) the trees with the brightest leaves will have higher fitness. Relative to green leaves, redder foliage contained higher concentrations of polygodial, a sesquiterpene dialdehyde known to have strong antifeedant properties, and incurred less insect feeding damage. Redder trees hosted fewer Ctenopseustis spp. leafroller larvae than neighbouring matched green trees. Contrary to the predictions of the leaf signalling hypothesis, there was no difference in any of the measured fitness parameters between red and green trees, indicating that the leaf colour polymorphism in P. colorata is stable. 2) Many insects are sensitive to volatile organic compounds (VOCs), however the role of VOCs in plant-herbivore signalling has not been investigated. I analysed VOCs released from undamaged, herbivore- and mechanically-damaged red and green leaves of P. colorata, and the olfactory preferences of brownheaded leafroller (C. obliquana) larvae. While the VOC profiles of browsed and unbrowsed leaves were statistically distinguishable, the VOC profiles released from intact, herbivore-, and mechanically-damaged P. colorata leaves did not reliably identify leaf colour. Moreover, naïve and experienced C. obliquana larvae displayed no preference for the volatiles from mechanically-damaged red or green leaves. Therefore, I concluded that VOC compounds are not likely to play a large role in mediating insect herbivore-plant interactions in P. colorata. 3) Studies of leaf signalling rarely consider the influence of the light-absorbing properties of non-green pigments upon photosynthesis. I compared the photosynthetic and photoinhibitory responses of red and green leaves from matched, neighbouring pairs of P. colorata of contrasting colour. Redder P. colorata leaves in the field had a lower maximum photosynthetic assimilation rate than matched green leaves from neighbouring trees. However, I was unable to detect any measurable advantage in terms of photoprotection in the red P. colorata leaves as indicated by chlorophyll fluorescence profiles. My results indicate that the presence of anthocyanin pigments within non-senescing leaves may impose a slight photosynthetic cost to the plant. 4) I used literature searches, field surveys and laboratory bioassays to identify which invertebrate herbivores are most likely to participate in leaf-signalling interactions with P. colorata. Feeding preference bioassays showed that brownheaded leafrollers (C. obliquana and C. herana) and Auckland tree weta (Hemideina thoracica) preferentially consumed leaf material from green than red P. colorata leaves. Results from these bioassays, combined with my field surveys suggest that Ctenopseustis spp. leafroller larvae are the most likely coevolution partners for P. colorata. 5) There is a well-established link between nitrogen deficiency and leaf reddening. Additionally, leaf nutrients can influence foraging behaviour and performance of insect herbivores. I measured N and C contents of leaves from neighbouring matched pairs of red and green P. colorata. There were no significant differences in the amounts of, or ratio between, N and C between matched red and green leaves. This result indicates that differences in colour and herbivory among P. colorata leaves are not attributable to differences in leaf nutrients. Taken together, my results suggest that foliar anthocyanins in P. colorata do function as visual signals, however their effect on herbivory is small. Additionally, interindividual variation in non-senescing leaf colour in P. colorata may be stable due to a trade off between signalling and photosynthesis. Discussions of leaf signalling need to follow the examples of other fields studying the interactions between plants and insects and move from overly simple models to those that incorporate more of the complexity that is observed in the natural world.

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“…In order to grow and reproduce, herbivorous insects must acquire nutrients, and therefore make host selection decisions based upon the nutrient content of their food (Behmer 2009). A diet of poor quality food can lead to impaired development and survival of insect herbivores (Calvo and Molina 2010). Therefore, a correlation between reduced insect abundance, or reduced damage, with leaf colour may be the result of interactions between plant nutritional status and insect nutritional requirements.…”

Section: Post-contact Correlated Cues -Leaf Nutrientsmentioning

confidence: 99%

Do foliar anthocyanin pigments in horopito (Pseudowintera colorata) function as visual signals to deter insect herbivores?

Menzies¹

0

View full text Add to dashboard Cite

Anthocyanin pigments are synthesised in the leaves of many plants, however the adaptive significance of these pigments is not entirely understood. It has been postulated that their red colours may function as visual signals through coevolution between herbivorous insects and their host tree species, though the hypothesis lacks solid empirical evidence. I investigated the leaf signalling hypothesis using Pseudowintera colorata, focusing on five areas: 1) I exploited the natural polymorphism in leaf colour of P. colorata to test the predictions that (i) bright leaf colour is a reliable signal of a plant’s defensive commitment; (ii) insects in the field avoid trees that are brightly coloured; and (iii) the trees with the brightest leaves will have higher fitness. Relative to green leaves, redder foliage contained higher concentrations of polygodial, a sesquiterpene dialdehyde known to have strong antifeedant properties, and incurred less insect feeding damage. Redder trees hosted fewer Ctenopseustis spp. leafroller larvae than neighbouring matched green trees. Contrary to the predictions of the leaf signalling hypothesis, there was no difference in any of the measured fitness parameters between red and green trees, indicating that the leaf colour polymorphism in P. colorata is stable. 2) Many insects are sensitive to volatile organic compounds (VOCs), however the role of VOCs in plant-herbivore signalling has not been investigated. I analysed VOCs released from undamaged, herbivore- and mechanically-damaged red and green leaves of P. colorata, and the olfactory preferences of brownheaded leafroller (C. obliquana) larvae. While the VOC profiles of browsed and unbrowsed leaves were statistically distinguishable, the VOC profiles released from intact, herbivore-, and mechanically-damaged P. colorata leaves did not reliably identify leaf colour. Moreover, naïve and experienced C. obliquana larvae displayed no preference for the volatiles from mechanically-damaged red or green leaves. Therefore, I concluded that VOC compounds are not likely to play a large role in mediating insect herbivore-plant interactions in P. colorata. 3) Studies of leaf signalling rarely consider the influence of the light-absorbing properties of non-green pigments upon photosynthesis. I compared the photosynthetic and photoinhibitory responses of red and green leaves from matched, neighbouring pairs of P. colorata of contrasting colour. Redder P. colorata leaves in the field had a lower maximum photosynthetic assimilation rate than matched green leaves from neighbouring trees. However, I was unable to detect any measurable advantage in terms of photoprotection in the red P. colorata leaves as indicated by chlorophyll fluorescence profiles. My results indicate that the presence of anthocyanin pigments within non-senescing leaves may impose a slight photosynthetic cost to the plant. 4) I used literature searches, field surveys and laboratory bioassays to identify which invertebrate herbivores are most likely to participate in leaf-signalling interactions with P. colorata. Feeding preference bioassays showed that brownheaded leafrollers (C. obliquana and C. herana) and Auckland tree weta (Hemideina thoracica) preferentially consumed leaf material from green than red P. colorata leaves. Results from these bioassays, combined with my field surveys suggest that Ctenopseustis spp. leafroller larvae are the most likely coevolution partners for P. colorata. 5) There is a well-established link between nitrogen deficiency and leaf reddening. Additionally, leaf nutrients can influence foraging behaviour and performance of insect herbivores. I measured N and C contents of leaves from neighbouring matched pairs of red and green P. colorata. There were no significant differences in the amounts of, or ratio between, N and C between matched red and green leaves. This result indicates that differences in colour and herbivory among P. colorata leaves are not attributable to differences in leaf nutrients. Taken together, my results suggest that foliar anthocyanins in P. colorata do function as visual signals, however their effect on herbivory is small. Additionally, interindividual variation in non-senescing leaf colour in P. colorata may be stable due to a trade off between signalling and photosynthesis. Discussions of leaf signalling need to follow the examples of other fields studying the interactions between plants and insects and move from overly simple models to those that incorporate more of the complexity that is observed in the natural world.

show abstract

Differences in Foliage Affect Performance of the Lappet Moth,Streblote panda: Implications for Species Fitness

Cited by 8 publications

References 39 publications

Lepidoptera-specific insecticide used to suppress gypsy moth outbreaks may benefit non-target forest Lepidoptera

Lepidoptera-specific insecticide used to suppress gypsy moth outbreaks may benefit non-target forest Lepidoptera

Do foliar anthocyanin pigments in horopito (Pseudowintera colorata) function as visual signals to deter insect herbivores?

Do foliar anthocyanin pigments in horopito (Pseudowintera colorata) function as visual signals to deter insect herbivores?

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