Floral sex and the fossil insect

Kvaček

Mostovski

2007

TAXON

121

155

Recent focus on plant‐insect associations during the angiosperm radiation from the last 30 million years of the Early Cretaceous has inadvertently de‐emphasized a similar but earlier diversification that occurred among gymnosperms. The existence of gymnosperm‐insect associations during the preangiospermous Mesozoic is evidenced by mouthparts capable of reaching and imbibing pollination drops or similar fluids, availability of pollen types consistent with entomophily, and opportunities for related consumption of pollen, seeds, and reproductively associated tissues in major seed‐plant groups, namely seed ferns, conifers, cycads, bennettitaleans, and gnetaleans. Based on stereotypical plant damage, head‐adherent pollen, gut contents, wing structure, mouthpart morphology and insect damage to plant reproductive organs, the likely nectarivores, pollinivores and pollinators were orthopterans, phasmatodeans, webspinners, sawflies and wasps, moths, beetles, mecopteroids, and true flies. These associations are ranked from possible to probable although the last three insect clades provide the strongest evidence for pollinator activity. We document two mid Cretaceous examples of these associations—cycadeoideaceous bennettitaleans and beetles and a cheirolepidiaceous conifer and flies—for which there are multiple lines of evidence for insect consumption of plant reproductive tissues but also pollination mutualisms. These data highlight the independent origin of a major phase of plant‐insect pollinator‐related associations during the mid Mesozoic that served as a prelude for the separate, iterative and later colonization of angiosperms.

Section: Insects As Consumers Of Nectar Po Llen and Associ-ated Reprmentioning

confidence: 99%

Pollination drops, pollen, and insect pollination of Mesozoic gymnosperms

Kvaček

Mostovski

2007

TAXON

121

155

“…Additionally the seeds of an extinct gingkophyte were used by caddisfly naiads to construct cases (159). At Orapa, Botswana, dated as Cenomanian (93 Ma) in age, a glimpse into an early Late Cretaceous insect fauna reveals weevils with well-preserved, decurved beaks (171), staphylinid beetles with typical mandibulate mouthparts (269), and a tipulid fly (268) housing an elongate rostrum 0.3 cm long, the tip bearing elongate, five-segmented palps and a small labellum, interpreted as a modificadon for nectarivory (267,268).…”

Section: Approaches Centered On the Fossil Recordmentioning

confidence: 99%

Insect Mouthparts: Ascertaining the Paleobiology of Insect Feeding Strategies

1997

Annu. Rev. Ecol. Syst.

244

209

One of the most intensively examined and abundantly documented structures in the animal world is insect mouthparts. Major structural types of extant insect mouthparts are extensive, consisting of diverse variations in element structure within each of the five mouthpart regions—labrum, hypopharynx, mandibles, maxillae, and labium. Numerous instances of multielement fusion both within and among mouthpart regions result in feeding organs capable of ingesting in diverse ways foods that are solid, particulate, and liquid in form. Mouthpart types have a retrievable and interpretable fossil history in well-preserved insect deposits. In addition, the trace-fossil record of insect-mediated plant damage, gut contents, coprolites, and insect-relevant floral features provides complementary data documenting the evolution of feeding strategies during the past 400 million years. From a cluster analysis of insect mouthparts, I recognize 34 fundamental mouthpart classes among extant insects and their geochronological evolution by a five-phase pattern. This pattern is characterized, early in the Devonian, by coarse partitioning of food by mandibulate and piercing-and-sucking mouthpart classes, followed by a rapid rise in herbivore mouthpart types for fluid- and solid-feeding during the Late Carboniferous and Early Permian. Mouthpart innovation during the Late Triassic to Early Jurassic added mouthpart classes for fluid and aquatic particle-feeding. This ecomorphological expansion of mouthpart design was associated with the radiation of holometabolous insects, especially Diptera. The final phase of mouthpart class expansion occurred during the Late Jurassic and Early Cretaceous, with addition of surface-fluid-feeding mouthpart classes that subsequently became important during the ecological expansion of angiosperms. Conclusions about the evolution of mouthpart design are based on the mapping of phenetic mouthpart classes onto (ideally) cladistic phylogenies of lineages bearing those same mouthpart classes. The plotting of phenetic and associated ecological attributes onto baseline phylogenies is one of the most important uses of cladistic data.

“…Notably, these mid-Mesozoic forms occur in deposits that either antedate the advent of angiosperms, or if contemporaneous with angiosperms (Sun et al, 1998), were relict Late Jurassic holdovers that occur in deposits lacking deep-throated angiosperm flowers (Labandeira 1998c). Deep-throated flowers do not occur until a few tens of millions of years later during the Late Cretaceous (Rayner and Waters, 1991;Zaitzev, 1998). The temporal occurrence of these brachyceran flies most likely indicates pollination of seed plants with a pollination drop mechanism (Labandeira, 1998c).…”

Section: Labandeira-paleobiology Of Pollinationmentioning

confidence: 99%

The Paleobiology of Pollination and its Precursors

2000

Paleontol. Soc. pap.

Perhaps the most conspicuous of associations between insects and plants is pollination. Pollinating insects are typically the first and most obvious of interactions between insects and plants when one encounters a montane meadow or a tropical woodland. The complex ecological structure of insect pollinators and their host plants is a central focus within the ever-expanding discipline of plant-insect interactions. The relationships between plants and insects have provided the empirical documentation of many case-studies that have resulted in the formulation of biological principles and construction of theoretical models, such as the role of foraging strategy on optimal plant-resource use, the advantages of specialized versus generalized host preferences as viable feeding strategies, and whether “pollination syndromes” are meaningful descriptions that relate flower type to insect mouthpart structure and behavior (Roubik, 1989; Ollerton, 1996; Waser et al., 1996; Johnson and Steiner, 2000). Much of the recent extensive discussion of plant-insect associations has centered on understanding the origin, maintenance, and evolutionary change in plant/pollinator associations at ecological time scales and increasingly at longer-term macroevolutionary time intervals (Armbruster, 1992; Pellmyr and Leebens-Mack, 1999). Such classical plant-insect association studies—cycads and cycad weevils, figs and fig wasps, and yuccas and yucca moths—were explored at modern time scales and currently are being examined through a long-term geologic component that involves colonization models based on cladogenetic events of plant and insect associates, buttressed by the fossil record (Farrell, 1998; Pellmyr and Leebens-Mack, 1999; A. Herre,pers. comm.). In addition to tracing modern pollination to the earlier Cenozoic and later Mesozoic, there is a resurgence in understanding the evolutionary history of earlier palynivore taxa (spore, prepollen and pollen consumers), which led toward pollination as a mutualism (Scott et al., 1992).