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Plant-insect interactions from Middle Triassic (late Ladinian) of Monte Agnello (Dolomites, N-Italy)-initial pattern and response to abiotic environmental perturbations.

Wappler T, Kustatscher E, Dellantonio E - PeerJ (2015)

Bottom Line: The flora from Monte Agnello is distinctive, due to its preservation in subaerially deposited pyroclastic layers with exceptionally preserved details.Thus, the para-autochthonous assemblage provides insights into environmental disturbances, caused by volcanic activity, and how they profoundly affected the structure and composition of herbivory patterns.These DT patterns show that external foliage feeders, piercer-and-suckers, leaf miners, gallers, and oviposition culprits were intricately using almost all tissue types from the dominant host plants of voltzialean conifers (e.g., Voltzia), horsetails, ferns (e.g., Neuropteridium, Phlebopteris, Cladophlebis and Thaumatopteris), seed ferns (e.g., Scytophyllum), and cycadophytes (e.g., Bjuvia and Nilssonia).

View Article: PubMed Central - HTML - PubMed

Affiliation: Steinmann Institute, University of Bonn , Bonn , Germany.

ABSTRACT
The Paleozoic-Mesozoic transition is characterized by the most massive extinction of the Phanerozoic. Nevertheless, an impressive adaptive radiation of herbivorous insects occurred on gymnosperm-dominated floras not earlier than during the Middle to Late Triassic, penecontemporaneous with similar events worldwide, all which exhibit parallel expansions of generalized and mostly specialized insect herbivory on plants, expressed as insect damage on a various plant organs and tissues. The flora from Monte Agnello is distinctive, due to its preservation in subaerially deposited pyroclastic layers with exceptionally preserved details. Thus, the para-autochthonous assemblage provides insights into environmental disturbances, caused by volcanic activity, and how they profoundly affected the structure and composition of herbivory patterns. These diverse Middle Triassic biota supply extensive evidence for insect herbivore colonization, resulting in specific and complex herbivory patterns involving the frequency and diversity of 20 distinctive damage types (DTs). These DT patterns show that external foliage feeders, piercer-and-suckers, leaf miners, gallers, and oviposition culprits were intricately using almost all tissue types from the dominant host plants of voltzialean conifers (e.g., Voltzia), horsetails, ferns (e.g., Neuropteridium, Phlebopteris, Cladophlebis and Thaumatopteris), seed ferns (e.g., Scytophyllum), and cycadophytes (e.g., Bjuvia and Nilssonia).

No MeSH data available.


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Plant and damage composition within the single sub-localities.Pie charts showing the frequency specimen data by (A). Host plant abundance (pooled in higher taxonomic ranks). (B)–(D) Damage composition. MA1, MA5, MA7, MA8, fossil sites.
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fig-4: Plant and damage composition within the single sub-localities.Pie charts showing the frequency specimen data by (A). Host plant abundance (pooled in higher taxonomic ranks). (B)–(D) Damage composition. MA1, MA5, MA7, MA8, fossil sites.

Mentions: Plant material is generally preserved at the base of the “explosion breccia” at an angle to the bedding rather than compacted into a single horizon. Transport distance, therefore, must have been short, and burial was likely rapid. Thus, the fossil leaf assemblages must be considered as para-autochthonous (e.g., Hanley et al., 2007). Minimal transport allows us to document considerable changes in species composition and insect folivory over short distances and recognize possible heterogeneity in the structure and composition of the source plant communities and their associated herbivores. Large-scale disturbances may profoundly alter the composition and structure of plant communities and are rarely uniform in their influence on vegetation (Kustatscher, Dellantonio & Van Konijnenburg-van Cittert, 2014). Variations of floral composition and insect herbivore damage at the four sub-localities (MA1, MA5, MA7, MA8) censused are shown in Fig. 4 and Table 4. MA1 has the highest floral diversity (22 ssp.), followed by MA5 (16 ssp.) and MA7 (15 ssp.). MA8 is an extremely low-diversity flora (7 ssp.). Interestingly, all sites are strongly dominated by a single plant group representing in all cases over half of the characteristic plant material at that site. The most abundant plant lineage at MA5–MA8 is conifers, whereas at MA1 57% of the taphocoenosis is composed of cycadophytes. However, when analyzing herbivory on individual host groups at the four sub-localities, total damage frequency and external foliage feeding is overwhelmingly found on seed-fern hosts (Fig. 4), except MA7 where the preferred host-plants are cycadophytes.


Plant-insect interactions from Middle Triassic (late Ladinian) of Monte Agnello (Dolomites, N-Italy)-initial pattern and response to abiotic environmental perturbations.

Wappler T, Kustatscher E, Dellantonio E - PeerJ (2015)

Plant and damage composition within the single sub-localities.Pie charts showing the frequency specimen data by (A). Host plant abundance (pooled in higher taxonomic ranks). (B)–(D) Damage composition. MA1, MA5, MA7, MA8, fossil sites.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4419555&req=5

fig-4: Plant and damage composition within the single sub-localities.Pie charts showing the frequency specimen data by (A). Host plant abundance (pooled in higher taxonomic ranks). (B)–(D) Damage composition. MA1, MA5, MA7, MA8, fossil sites.
Mentions: Plant material is generally preserved at the base of the “explosion breccia” at an angle to the bedding rather than compacted into a single horizon. Transport distance, therefore, must have been short, and burial was likely rapid. Thus, the fossil leaf assemblages must be considered as para-autochthonous (e.g., Hanley et al., 2007). Minimal transport allows us to document considerable changes in species composition and insect folivory over short distances and recognize possible heterogeneity in the structure and composition of the source plant communities and their associated herbivores. Large-scale disturbances may profoundly alter the composition and structure of plant communities and are rarely uniform in their influence on vegetation (Kustatscher, Dellantonio & Van Konijnenburg-van Cittert, 2014). Variations of floral composition and insect herbivore damage at the four sub-localities (MA1, MA5, MA7, MA8) censused are shown in Fig. 4 and Table 4. MA1 has the highest floral diversity (22 ssp.), followed by MA5 (16 ssp.) and MA7 (15 ssp.). MA8 is an extremely low-diversity flora (7 ssp.). Interestingly, all sites are strongly dominated by a single plant group representing in all cases over half of the characteristic plant material at that site. The most abundant plant lineage at MA5–MA8 is conifers, whereas at MA1 57% of the taphocoenosis is composed of cycadophytes. However, when analyzing herbivory on individual host groups at the four sub-localities, total damage frequency and external foliage feeding is overwhelmingly found on seed-fern hosts (Fig. 4), except MA7 where the preferred host-plants are cycadophytes.

Bottom Line: The flora from Monte Agnello is distinctive, due to its preservation in subaerially deposited pyroclastic layers with exceptionally preserved details.Thus, the para-autochthonous assemblage provides insights into environmental disturbances, caused by volcanic activity, and how they profoundly affected the structure and composition of herbivory patterns.These DT patterns show that external foliage feeders, piercer-and-suckers, leaf miners, gallers, and oviposition culprits were intricately using almost all tissue types from the dominant host plants of voltzialean conifers (e.g., Voltzia), horsetails, ferns (e.g., Neuropteridium, Phlebopteris, Cladophlebis and Thaumatopteris), seed ferns (e.g., Scytophyllum), and cycadophytes (e.g., Bjuvia and Nilssonia).

View Article: PubMed Central - HTML - PubMed

Affiliation: Steinmann Institute, University of Bonn , Bonn , Germany.

ABSTRACT
The Paleozoic-Mesozoic transition is characterized by the most massive extinction of the Phanerozoic. Nevertheless, an impressive adaptive radiation of herbivorous insects occurred on gymnosperm-dominated floras not earlier than during the Middle to Late Triassic, penecontemporaneous with similar events worldwide, all which exhibit parallel expansions of generalized and mostly specialized insect herbivory on plants, expressed as insect damage on a various plant organs and tissues. The flora from Monte Agnello is distinctive, due to its preservation in subaerially deposited pyroclastic layers with exceptionally preserved details. Thus, the para-autochthonous assemblage provides insights into environmental disturbances, caused by volcanic activity, and how they profoundly affected the structure and composition of herbivory patterns. These diverse Middle Triassic biota supply extensive evidence for insect herbivore colonization, resulting in specific and complex herbivory patterns involving the frequency and diversity of 20 distinctive damage types (DTs). These DT patterns show that external foliage feeders, piercer-and-suckers, leaf miners, gallers, and oviposition culprits were intricately using almost all tissue types from the dominant host plants of voltzialean conifers (e.g., Voltzia), horsetails, ferns (e.g., Neuropteridium, Phlebopteris, Cladophlebis and Thaumatopteris), seed ferns (e.g., Scytophyllum), and cycadophytes (e.g., Bjuvia and Nilssonia).

No MeSH data available.


Related in: MedlinePlus