The background image is a scanning electron micrograph of the head of Haptoncus tahktajanii (Nitidulidae, Coleoptera), photographed by Al Soeldner, Oregon State University Electron Microscopy Laboratory. Haptoncus tahktajanii is a phytophagous associate of the island endemic tree Degeneria vitiensis (Degeneriaceae, Magnoliales, Magnolianae). Field work on Degeneriaceae of the Fiji Islands was sponsored by a grant from the National Geographic Society.
Computer-assisted Exercise in the Paleobiology of Insect Vision and the Floral Tool Kit:
According to Grimaldi and Engel (page 469, Figure 12.1, 2005) Panorpida, which are a sister group to the Hymenoptera (ants, bees, and wasps), diverged more than 290 MYA, roughly coincident with the angiosperm-gymnosperm split. There are estimates published in the literature that crown group flowering plants originated 221 MYA in the Middle Triassic (Foster et al. 2017).
Several published papers help us to understand the paleobiology of pollination by insects from several disparate lines of thought (Chittka et al. 1994, Chittka 1996, Labandeira 1998, Dong Ren 1998, Labandeira 2000, Chittka et al. 2001, Dong Ren et al. 2009).
The scanning electron micrograph shown on the right-hand side of the page is the anterior front part of the head of Haptoncus tahktajanii (Nitidulidae, Coleoptera), the cucujiform phytophagous associate of the primitive magnoliid flowering plant Degeneria vitiensis (Degeneriaceae, Magnoliales, Magnoliidae). Many gustatory, olfactory, and visual sensory organs of the nitidulid beetle are visible in the image including antennae, sensillae, compound eyes, mandibles, maxillae, and labia, × 100.
Some of the floral organs of Degeneria vitiensis are covered with bright-yellow, oily exudate and emit volatile hydrocarbons (VOCs) including fragrant terpenes and acetate esters. What if any, of the nitidulid head capsule appendages pictured above, function as visual sensory receptors of UV-absorbing natural plant products? As a classroom or seminar exercise, design field experiments to answer this question, among others.
Nitidulids were collected by the author from flowers clipped from the canopy of Degeneria trees at the Mount Naitaradamu Study Area, Viti Levu, Fiji Islands in 1986. The National Geographic Society is acknowledged for providing research funding for this work. The photograph is by Al Soeldner of the Oregon State University Electron Microscope Laboratory.
After completing the problem on paleobotany and taphonomy, which is described on another page of this web site, design experiments using artificial 3-D printed constructs of whole plant organs to shed light on the paleobiology of arthropod and seed plant interactions.
Work published by Chittka (1996), Briscoe and Chittka (2001), and Chittka et al. (2001) are key toward understanding the paleobiology of panorpoids. Implications of these three studies toward an understanding of the deep time evolution of pollination mutualisms and color and scent perception by species of the "Big Five" holometabolous insect orders and late Paleozoic seed plants, when taking into account the paleobiology of the arthropod brain, are absolutely profound.
"It is likely that trichromacy existed prior to the advent of angiosperm flowers" (page 138, Chittka 1996).
Apply three-dimensional (3-D) printing technology to create artificial, dimorphic foliar or floral organs of a hypothetical Permo-carboniferous protoflower (reproductive short- [spur-] shoot) as a class science project. Carry-out experiments to prove or disprove ideas proposed by Briscoe, Chittka, Labandeira, and Dong Ren, among others.
Perform a Google Scholar literature search to retrieve publications guiding the design of experiments on insect sensory perception of the 3-D printed artificial constructs of reproductive short- (spur-) shoots to be doped with food rewards, scent, tactile cues, and/or ultraviolet-absorbing natural products. There are at least two examples in the library.
Anchor studies from the Chittka and Strausfeld labs (Chittka et al. 1994, Chittka 1996, Strausfeld et al. 1998, Briscoe and Chittka 2001, Chittka et al. 2001, Strausfeld 2009, Xiaoya Ma et al. 2012, Edgecombe et al. 2015, Xiaoya Ma et al. 2015) may provide clues.
When supported by paleobotanical evidence, were anthocyanic fertile short (spur) shoots of Permo-carboniferous seed plants visually discernable to pollinivores, paleodictyopterans, and predatory wasps in "sensory color space" (page 846, The use of floral morphospaces in evolutionary ecology: the sensory color space, Chartier et al. 2014)?
"Hence, a flower that stands out against green foliage can be predicted to be equally conspicuous against brown soil, grey stones and other inorganic backgrounds" (page 1505, Chittka et al. 1994).
Did protohymenopterans including sawflies (xyelids) possess mushroom bodies, optic lobes, and sensory tool kits necessary to visualize pigments of foliar organs, including protoflowers?
After reading the evo-devo primer presented in the previous section, were tool kit interactions between auxin, homeodomain protein TFs (CUC2, Class III HD-Zip, KNOTTED/ARP, WUSCHEL), and PIN proteins, present in foliar organs and reproductive short- (spur-) shoots of Paleozoic seed plants?
Does the foliar morphology and leaf-midrib anatomy of Permian delnorteas and evolsonias display the developmental fingerprint of a magnoliid or eudicot molecular tool kit?
If the Triassic seed plant Sanmiguelia lewisii displays a monocot tool kit fingerprint how does the review by Chanderbali et al. (2016) help us understand the evo-devo of flowers?
Based on the phenotypes of developmental regulation visible in detached and shed Permian seed plant leaf fossils, was the foliar tool kit of delnorteas, evolsonias, and retuse taeniopteroids underpinned by the same WOX homeobox genes, WUSCHEL homeodomain proteins, and CUC2 TFs as extant model flowering plant species?
How could a team of paleobiologists prove these ideas?
Can you apply techniques of phylogenetics to a paleobiological data set to zoom-in on this problem?
Answering some of the questions posed above might help us to better understand the paleobiology of flowers and arthropod vision. Mining and describing fossilized cones and protoflowers and documenting evidence of developmental fingerprints seen in detached and shed foliar and floral organs, might help paleobiologists calibrate seed plant molecular tool kit phylogenies.
Alvarez, J. M., J. Sohlberg, P. Engström, Tianqing Zhu, M. Englund, P. N. Moschou, and S. von Arnold. 2015. The WUSCHEL-RELATED HOMEOBOX 3 gene PaWOX3 regulates lateral organ formation in Norway spruce. New Phytologist 208(4): 1078–1088.
Briscoe, A. D. and L. Chittka. 2001. The evolution of color vision in insects. Annual Review of Entomology 46: 471–510.
Chanderbali, A. S., B. A. Berger, D. A. Howarth, P. S. Soltis, and D. E. Soltis. 2016. Evolving ideas on the origin and evolution of flowers: new perspectives in the genomic era. Genetics 202: 1255-1265.
Chartier, M., F. Jabbour, S. Gerber, P. Mitteroecker, H. Sauquet, M. von Balthazar, Y. Staedler, P. R. Crane, and J. Schönenberger. 2014. The floral morphospace - a modern comparative approach to study angiosperm evolution. New Phytologist 204: 841-853.
Chittka, L. 1996. Does bee color vision predate the evolution of flower color? Naturwissenschaften 83: 136-138.
Chittka, L., A. Schmidt, N. Troje, and R. Menzel. 1994. Ultraviolet as a component of flower reflections, and the colour perception of Hymenoptera. Vision Research 34: 1489-1508.
Chittka, L., J. Spaethe, A. Schmidt, and A. Hickelsberger. 2001. 6. Adaptation, constraint, and chance in the evolution of flower color and pollinator color vision. Pp. 106-126 In: L. Chittka and J. D. Thomson (eds.), Cognitive Ecology of Pollination, Animal Behaviour and Floral Evolution. Cambridge: Cambridge University Press, 344 pp.
Edgecombe, G. D., Xiaoya Ma, and N. J. Strausfeld. 2015. Unlocking the early fossil record of the arthropod central nervous system. Philosophical Transactions of the Royal Society of London, Series B, Biological Sciences 370(1684): DOI 10.1098/rstb.2015.0038.
Foster, C. S. P., H. Sauquet, M. van der Merwe, H. McPherson, M. Rossetto, and S. Y. W. Ho. 2017. Phylogenomic timescale for angiosperm evolution: evaluating the impact of genomic data and priors on Bayesian estimates of the angiosperm evolutionary timescale. Systematic Biology XX: XXX-XXX.
Grimaldi, D. and M. S. Engel. 2005. Evolution of the Insects. Cambridge: Cambridge University Press, 755 pp.
Labandeira, C. C. 1998. How old is the flower and the fly? Science 280: 57-59.
Labandeira, C. C. 2000. The paleobiology of pollination and its precursors. Pp. 233-269 In: R. A. Gastaldo and W. A. DiMichele (eds.), Phanerozoic Terrestrial Ecosystems. Paleontological Society Papers 6: 233-269.
Ma, Xiaoya, G. D. Edgecombe, Xianguang Hou, T. Goral, and N. J. Strausfeld. 2015. Preservational pathways of corresponding brains of a Cambrian euarthropod. Current Biology 25(22): 2969-2975.
Ma, Xiaoya, X. Hou, G. D. Edgecombe, and N. J. Strausfeld. 2012. Complex brain and optic lobes in an early Cambrian arthropod. Nature 490(7419): 258-262.
Ren, Dong. 1998. Flower-associated Brachycera flies as fossil evidence for Jurassic angiosperm origins. Science 280: 85-88.
Ren, Dong, C. C. Labandeira, J. A. Santiago-Blay, A. Rasnitsyn, C-K. Shih, A. Bashkuev, M. A. V. Logan, C. L. Hotton, and D. L. Dilcher. 2009. A probable pollination mode before angiosperms: Eurasian, long-proboscid scorpionflies. Science 326(5954): 840-847.
Strausfeld, N. J. 2009. Brain organization and the origin of insects: an assessment. Proceedings of the Royal Society of London, Series B, Biological Sciences 276(1664): 1929-1937.
Strausfeld, N. J., L. Hansen, Y. Li, R. S. Gomez, and K. Ito. 1998. Evolution, discovery, and interpretations of arthropod mushroom bodies. Learning and Memory 5(1): 11-37.