SCIENTIFIC CORRESPONDENCE

narrow pores, through which the amphi­ The and the amphipod pods gained access to the stamen (b in the figure). The acted as a block SIR - The aspidistra is an aberrant mem­ consumed by an organism. to rain and other flower-damaging ber of Convallariaceae (: To detect which organisms had left arthropods, and as a gate for the selected ) 1, which bears bell-shaped these faeces, five arthropod pollinators. (2) The amphipods visited the flowers close to the ground and was (Sphaerillo sp. (Crustacea: Isopoda: flower to eat pollen, and left the flower thought to be unique in being pollinated Arrnadillidae), Burmoniscus sp. (Isopoda: with pollen attached to the body. (3) The by slugs2• The system of the Philosciidae ), Platorchestia japonica amphipods cannot fly but are very able aspidistra, however, has not yet been (: Talitridae), Hypogastrura sp. hoppers, and could thus transport pollen directly reported in its original area of dis­ (Insecta: Collembola: Hypogastruridae) long distances. tribution of East Asia. Recent observa­ and Scolopocryptops sp. (Chilopoda: Cryp­ Although the terrestrial talitrid tions made in its native habitat in Japan topidae)) most frequently found in amphipods are thought to have originated suggested that is pollinat­ aspidistra flowers were observed in the in Gondwanaland and reached South­ ed by pollen-eating, terrestrial amphipods. laboratory. These arthropods, collected in East Asia on drifting land fragments'·', the The most unique characteristic of the or around the flowers, were introduced in Japanese species are thought to have aspidistra is a large, fleshy, disk-like plastic cases with aspidistra flowers which adapted to terrestrial habitats rather stigma, which entirely blocks the lower had been cut transversely. Among arthro- recently from supralittoral habitats'·'. To inside corolla containing detect whether the unique pollination the stamens (a, b in the fig­ system is ubiquitous amongst Aspidistra, ure). The stigma of Aspidis­ observations are needed in the area of its tra lurida is believed to act greatest diversity, the southern parts of as an attractant and reward . for slugs, which partly eat Makoto Kato the stigma, gaining access Biological Laboratory, Yoshida College, to the stamens below, Kyoto University, and thus taking part in Sakyo, Kyoto 606-01, Japan pollination2• Aspidistra elatior Bl. is widely cultivated in China Cortical areas in and Japan, but is thought to be indigenous to only a few visual awareness small islands in the south­ ern part of Japan'. The SIR - I commend Crick and Koch I for higher altitudes (300-622 their serious and innovative neurobiol­ m) of the island of ogical approach to the problem of visual Kuroshima in Kagoshima awareness and agree with several of their Prefecture are covered ideas, such as those for differential explicit with evergreen oak forests representations from cortex to cortex. whose understory is Space, however, constrains me to confine covered with . subsequent comments largely to areas of We made observations of disagreement. pollinator visits to the Crick and Koch hypothesize that flowers here in March 1995. "activity in Vl does not directly enter No flowers were found A flower of Aspidistra efatior and its amphipod pollinator, awareness". I feel that they should clarify with stigma damage. Platorchestia j aponica. a, Vertical section; b, top view of a an ambiguity in their text and their Fig. 1: Among 89 flowers sampled stigma. An arrow shows a pore through which amphipods do they believe that frontal cortical areas and dissected, 37% were enter below. c, Vertical section of a flower being visited by an are involved in visual awareness, and if so, visited by various arthro­ amphipod; d, an amphipod feeding on pollen. why? I also challenge their premise that pods; isopods (8% ), only those visual areas that project direct­ amphipods (8%) (c in the figure), col­ pods studied, amphipods and collem­ ly to brain regions that "contemplate, plan lembolans (14% ), thysanurans (1 % ), bolans ate pollen (d in the figure), and and execute voluntary motor outputs" dipterans (3%, predaceous larvae of amphipods excreted faeces which were can participate directly in awareness. I Mycetophilidae) and chiropods (2% ). identical with those left in the flowers in disagree with claims that existing physio­ In 28% of the flowers, yellowish-white their natural habitat. The only slug species logical and psychophysical evidence faeces composed of digested pollen were found on the islands, Granulilimax fusci­ supports their hypothesis, and offer here present, but no visitors were found. In comis (Mollusca: Pulmonata), preyed on evidence against excluding Vl and V2 these flowers, almost all pollen grains had snails and never visited the flower. from the process of visual awareness. disappeared. Pollen would accumulate Because anthers ofAspidistra are isolat­ Neural correlates of working spatial and in the bottom of the flower if not ed from the upper disk-like stigma, self­ object memory are found in premotor pollination is unlikely if the flower is not cortex2• Ablations of frontal cortex do not

1. Dahlgren, R., Clifford, H. & Yeo. P. The Families of the visited by an organism. Seed-set con­ affect visual acuity but may produce (Springer, New York, 1985). firmed in the natural habitats and the evi­ 'neglect', a stimulus- response failure in the 2. Richards, A. J. Breeding Systems (Allen & Unwin. dence of frequent amphipod visits to absence of a sensory defect, attributed to London, 1986). 3 . Sako, S. & Maruno, K. Rep. Kagoshima Univ. For. 16, flowers suggest that the amphipod is the "attentional components of motor respon­ 33- 62 (1985). most likely candidate for the pollinator. ses, and not elementary, space-related vis­ 4 . Hurley, D. E. Am. Zoo/. 8, 327- 53 (1968). 3 5 . Friend, J. A. A. Rev. Ent. 31, 25- 48 (1986). The pollinator status of the amphipod ual perception" • If Crick and Koch believe 6 . Morino, H. Pub/. Seto mar. Biol. Lab. 22, 171- 193 is further reinforced by the following evi­ that these cortices and/or premotor and (1975). 7. Bousfield, E. L. Bishop Mus. Spec. Pub/. 72, 171-210 dence. (1) Between the disk-like stigma motor cortex are involved in visual aware­ (1984). and the corolla, there are four small, ness, I ask them to provide such evidence. NATURE · VOL 377 · 28 SEPTEMBER 1995 293

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