skip to main content

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • ‘Mother knows best’: Maternal oviposition effects of a range‐expanding insect herbivore degrade coastal wetlands by targeting juvenile foundation plant species
Title: ‘Mother knows best’: Maternal oviposition effects of a range‐expanding insect herbivore degrade coastal wetlands by targeting juvenile foundation plant species
Abstract

Species range expansion induced by climate change and human activities threaten native populations and communities across the biosphere. Insect herbivores, important consumers of plants, are known to expand or contract their range under global change, with potential consequences to the newly reached environment. The selection of oviposition sites by herbivorous insects could notably impact offspring performance. However, the role of such effects in impacting the receiving ecosystem has been rarely explored. Here, we provide the first evidence showing that a terrestrial range‐expanding phytophagous wood‐borer moth (Zeuzera leuconotumButler) heavily attacked the saplings of a foundation plant species tamarisk (Tamarix chinensis) in salt marshes. Long‐term field surveys and laboratory behaviour experiments revealed that the oviposition preference of adult females was beneficial to their larval performance. The preference to oviposit on young branches of the new host plants, which were often softer and contained enough nutrients for larval development, indicates that females could still make the right choice on novel host‐plants. This finding supports the ‘mother knows best’ hypothesis that female insects will evolve to oviposit on hosts on which their offspring fare best. Consequently, the survival of host‐plant saplings decreased dramatically under this top‐down control, revealing that herbivory of this range‐expanding insect has a profound negative impact on the recruitment and succession of coastal foundation species, thereby potentially leading to saltmarsh degradation. These findings highlight the importance of the maternal oviposition effects in range‐expanding insects and how these populations can establish using novel host‐plants and threaten coastal wetlands.

  more » « less
PAR ID:
10376182
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Land Degradation & Development
Volume:
33
Issue:
16
ISSN:
1085-3278
Page Range / eLocation ID:
p. 3023-3035
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ( , PeerJ)
    null (Ed.)
    Background Oviposition decisions are critical to the fitness of herbivorous insects and are often impacted by the availability and condition of host plants. Monarch butterflies ( Danaus plexippus ) rely on milkweeds ( Asclepias spp.) for egg-laying and as food for larvae. Previous work has shown that monarchs prefer to oviposit on recently regrown plant tissues (after removal of above-ground biomass) while larvae grow poorly on plants previously damaged by insects. We hypothesized that these effects may depend on the life-history strategy of plants, as clonal and non-clonal milkweed species differ in resource allocation and defense strategies. Methodology/Principal Findings We first confirmed butterfly preference for regrown tissue in a field survey of paired mowed and unmowed plots of the common milkweed A. syriaca . We then experimentally studied the effects of plant damage (comparing undamaged controls to plants clipped and regrown, or damaged by insects) on oviposition choice, larval performance, and leaf quality of two closely related clonal and non-clonal species pairs: (1) A. syriaca and A. tuberosa , and (2) A. verticillata and A. incarnata . Clonal and non-clonal species displayed different responses to plant damage, impacting the proportions of eggs laid on plants. Clonal species had similar mean proportions of eggs on regrown and control plants (≈35–40% each), but fewer on insect-damaged plants (≈20%). Meanwhile non-clonal species had similar oviposition on insect-damaged and control plants (20–30% each) but more eggs on regrown plants (40–60%). Trait analyses showed reduced defenses in regrown plants and we found some evidence, although variable, for negative effects of insect damage on subsequent larval performance. Conclusions/Significance Overall, non-clonal species are more susceptible and preferred by monarch butterflies following clipping, while clonal species show tolerance to clipping and induced defense to insect herbivory. These results have implications for monarch conservation strategies that involve milkweed habitat management by mowing. More generally, plant life-history may mediate growth and defense strategies, explaining species-level variation in responses to different types of damage. 
    more » « less
  2. ; ; ; ( , Journal of Insect Science)
    Abstract

    Intensifying drought conditions across the western United States due to global climate change are altering plant–insect interactions. Specialist herbivores must find their host plants within a matrix of nonhosts, and thus often rely upon specific plant secondary chemistry for host location and oviposition cues. Climate-induced alterations to plant chemistry could thus affect female selection of larval food plants. Here, we investigated whether host-plant water limitation influenced oviposition preference in a threatened invertebrate: the monarch butterfly (Danaus plexippus). We found that females deposited more eggs on reduced-water than on well-watered narrowleaf milkweed plants (Asclepias fascicularis), but we could not attribute this change to any specific change in plant chemistry. Specialist herbivores, such as the monarch butterfly, which are tightly linked to specific plant cues, may experience shift in preferences under global-change conditions. Understanding oviposition preferences will be important to directing ongoing habitat restoration activities for this declining insect.

     
    more » « less
  3. ; ; ( , PLOS ONE)
    Mansour, Ramzi (Ed.)
    The preference-performance hypothesis explains host specificity in phytophagous insects, positing that host plants chosen by adults confer the greatest larval fitness. However, adults sometimes oviposit on plants supporting low larval success because the components of host specificity (adult preference, plant palatability, and larval survival) are non-binary and not necessarily correlated. Palatability (willingness to eat) is governed by chemical cues and physical barriers such as trichomes, while survival (ability to complete development) depends upon nutrition and toxicity. Absence of a correlation between the components of host specificity results in low-performance hosts supporting limited larval development. Most studies of specificity focus on oviposition behavior leaving the importance and basis of palatability and survival under-explored. We conducted a comprehensive review of 127 plant species that have been claimed or tested to be hosts for the monarch butterfly Danaus plexippus to classify them as non-hosts, low performance, or high performance. We performed a meta-analysis to test if performance status could be explained by properties of neurotoxic cardenolides or trichome density. We also conducted a no-choice larval feeding experiment to identify causes of low performance. We identified 34 high performance, 42 low performance, 33 non-hosts, and 18 species with unsubstantiated claims. Mean cardenolide concentration was greater in high- than low-performance hosts and a significant predictor of host status, suggesting possible evolutionary trade-offs in monarch specialization. Other cardenolide properties and trichome density were not significant predictors of host status. In the experiment, we found, of the 62% of larvae that attempted to eat low-performance hosts, only 3.5% survived to adult compared to 85% of those on the high-performance host, demonstrating that multiple factors affect larval host plant specificity. Our study is the first to classify all known host plants for monarchs and has conservation implications for this threatened species. 
    more » « less
  4. ; ; ; ( , Journal of Applied Entomology)
    Abstract

    The broad variation in host use among polyphagous insects is well documented but still poorly understood. In numerous pest insects, the proximate mechanisms responsible for variation in oviposition preference among host plants remain to be elucidated. The invasive crop pest,Drosophila suzukii, attacks a wide range of host fruits. Females prefer ovipositing on particular fruit media (blackberry, cherry, blackcurrant) that are rich in phosphorus. As phosphorus is known to be involved in female reproduction in insect species such as Drosophila, it could drive oviposition preference inD. suzukii. Phosphorus is either present as inorganic or organic phosphate in fruits. As the absolute content in macromolecules associated with phosphate in fruits (i.e. proteins and carbohydrates) do not affect oviposition inD. suzukii, we tested for the effect of inorganic phosphate on oviposition preference. We measured the egg‐laying preferences ofD. suzukiiin a choice environment containing 12 artificial media with increasing content in inorganic phosphate (monopotassium dihydrogen phosphate). In our assay,D. suzukiifemales did not prefer ovipositing in media with high inorganic phosphate content compared to media with lower inorganic phosphate content. As a confirmation, we verified the previous result of a higher female preference for media made of phosphorus‐rich fruits (blackberry, cherry, blackcurrant). The higher preference for phosphorus‐rich fruits could be driven by macromolecules containing phosphorus (e.g. phospholipids) or by the presence of one or more molecules that do not contain phosphorus, but that happen to be correlated to fruit phosphorus content. Studying the proximate mechanisms driving host use will ultimately help improve the management ofD. suzukiiand other crop pests.

     
    more » « less
  5. ; ; ; ; ; ( , Oecologia)
    Abstract

    Understanding the circumstances under which insect herbivores will adopt a novel host plant is a longstanding question in basic and applied ecology. While geographic variation in host use can arise through differences in both herbivore preference and plant characteristics, there is a tendency to attribute geographic variation in host use to regional differences in herbivore preference alone. This is especially true for herbivores specialized to one or a few plant species. We compared how geographic variation in herbivore preference and host plant origin shape regional differences in host plant use by the specialized herbivore,Euphydryas phaeton. In parts of its range,E. phaetonuses only a native host,Chelone glabra, while in others, it also uses an introduced host,Plantago lanceolata. We offered female butterflies from each region the non-native host plant sourced from both regions and compared their oviposition behavior. The non-native host was almost universally rejected by butterflies in the region where only the native plant is used. In the region where butterflies use both hosts, females accepted non-native plants from their natal region twice as often as non-native plants from the other region where they are not used. Acceptance differed substantially among individual butterflies within regions but not among plants within regions. Thus, both individual preference and regional differences in both the insect and non-native host contributed to the geographic variation in different ways. These results highlight that, in addition to herbivore preference, regional differences in perceived plant suitability may be an important driver of diet breadth.

     
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email