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From: Eric Gouda <E.J.Gouda at BIO.UU.NL>
Subject: article abstract
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A survey of the function of the lethal kettle traps of Arisaema (Araceae)=,=

with records of pollinating fungus gnats from Nepal
pp. 61-100 (doi:10.1006/bojl.1999.0317)

STEFAN VOGEL1, JOCHEN MARTENS2

1Institut f=FCr Botanik der Universit=E4t Wien, Rennweg 14, Vienna, A=-1030,=

Austria
2Institut f=FCr Zoologie der Universit=E4t Mainz, M=FCllerweg 6, Ma=inz,=
D-55099, 
Germany &Category=all&Journal=all"IDEAL Related Articles
(Received March 1999; accepted November 1999; published electronically Ma=y=

18, 2000)

Abstract
Evidence from recent research combined with an evaluation of the literatu=re=

indicates that Arisaema is adapted to pollination by fungus gnats. It=2=0
apparently shares this peculiarity among aroids only with the distantly= 
related genus Arisarum. In addition to previous records from Japan and= 
North America, systematic collections from nine Arisaema species during= 
several expeditions in the Himalayas in Nepal showed that, although other= 
less efficient insect groups may participate, the nematoceran families= 
Mycetophilidae and Sciaridae are the principal pollen vectors; they best= 
fit the pollination apparatus of the mainly (para)dioecious kettle trap= 
blossoms. A total of 16 fungus gnat genera (both Mycetophilidae and 
Sciaridae) comprising 47 identified species (among them one genus and 22= 
species new to science) were observed. Usually members of more than one= 
taxon are attracted per Arisaema species, and both sexes of gnats are=2=0
involved. Visitor sets differed to some degree, depending on host species=,=

area, and altitude; they do not, however, represent the complete fungus= 
gnat fauna of a region. Relevant traits of growth habit and inflorescence= 
structure are surveyed, and a detailed description of the pollination=2=0
process is given, based on observations made on specimens cultivated in= 
Europe, where vicariant fungus gnats are the pollinators. Attraction is= 
deceptive by mimicking olfactory, visual and tactile cues characteristic =of=

fungi where the gnat sexes normally meet and females oviposit. Odours=2=0
produced by osmophores (the spadix appendage or spathe tip) play the most= 
important part. The identified volatile compounds are mainly short-chaine=d=

aliphatic aldehydes and alcohols. Flagelliform osmophores of some species=,=

up to several dm long, reach the substrate and serve as conducting paths.= 
Gnats become imprisoned when they inadvertently slide down the inner wall= 
of the spathe tube. Its surface including the spadix is covered with 
ablative wax particles that inactivate the insects=BB tarsal pulvilli. =This=

gliding device, in some species reinforced by zones of imbricate papillae=,=

is irreversible, and no movements of floral parts allowing escape via the= 
spathe mouth occur. Anthesis lasts several weeks. In the male spathes,= 
victims are forced to wade through the pollen masses that have accumulate=d=

at the spathe's bottom; there they find an exit hole formed by local gapi=ng=

of the spathe rims. The female spathes lack such an aperture. After 
potentially depositing pollen on the stigmas during their efforts to 
escape, gnats are detained until death. Except for an autogamous subspeci=es=

of A. flavum Schott, the few monoecious taxa of Arisaema are protogynous= 
and possibly self-sterile. In monoecious A. tortuosum (Wall.)Schott, exit= 
forming is delayed until pollen release. Three Arisarum species that are= 
suspected to deviate in their floral syndrome are discussed along with= 
araceous genera possessing similar one-way pitfall mechanisms. Copyright= 
2000 The Linnean Society of London Key Words: floral deception - 
Mycetophilidae - osmophores - sapromyiophily - Sciaridae.

Corresponding author. E-mail: vogel at s1.botanik.univie.ac.at

+++
____               ____   E.J.Gouda at bio.uu.nl  http://www.uu.nl/botga=rd/
/ ___|_ __(_) __   / ___| ___  _   _  __| | __ _    Faxnr: +31 30 2535=177
| |__ | '__| |/ _| | |  _ / _ \| | | |/ _` |/ _` |   Prive:   Jungfrau =107
| |___| |  | | (_  | |_| | (_) | |_| | (_| | (_| |   NL - 3524 WJ  Utre=cht
\____|_|  |_|\__|  \____|\___/ \___/ \__,_|\__,_|   THE NETHERLANDS  (=NL)
Curator of UNIVERSITY BOTANIC GARDENS,  PO Box 80.162, NL-3508 TD UTRE=CHT
\ Listowner: Alpine-L, Arisaema-L, Bromelia-L, DELTA-L, Passiflora-L  =/
\__         Penstemon-L, Trillium-L (at Nic.SurfNet.NL)             _=_/

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<html>
A survey of the function of the lethal kettle traps of
Arisaema (Araceae), with records of pollinating fungus
gnats from Nepal 
pp. 61-100 (doi:10.1006/bojl.1999.0317) 
STEFAN VOGEL1, JOCHEN
MARTENS2 
1Institut f=FCr Botanik der Universit=E4t =Wien,
Rennweg 14, Vienna, A-1030, Austria 
2Institut f=FCr Zoologie der Univers=it=E4t
Mainz, M=FCllerweg 6, Mainz, D-55099, Germany
&amp;Category=all&amp;Journal=all&qu=ot;IDEAL
Related Articles 
(Received March 1999; accepted November 1999;
published electronically May 18, 2000) 
Abstract 
Evidence from recent resear=ch
combined with an evaluation of the
literature indicates that Arisaema<s=up>
is adapted to pollination=by
fungus gnats. It
apparently shares this peculiarity among aroids
only with the
distantly related genus Arisarum.<su=b>
In addition to previous
records from Japan and North
America, systematic<s=ub>
collections from nine Arisaema
species during
several expeditions in the Himalayas in Nepal
showed that,
although other less efficient
insect groups may
participate, the nematoce=ran
families Mycetophilidae and
Sciaridae are the princip=al
pollen vectors; they
best fit the pollination
apparatus of the mainly
(para)dioecious kettle trap blossoms. A
total of 16 fungus<su=p>
gnat genera (both
Mycetophilidae and Sciaridae)
comprising 47 identified
species (among them one genus and
22 species new to science=)
were observed. Usually
members of more than one taxon are
attracted per Arisaema
species, and both sexes o=f
gnats are involved. Visitor sets
differed to some degree, depending on
host species,
area, and altitude; they do not, however,<s=up>
represent the complete fu=ngus
gnat fauna of a region.
Relevant traits of growth habit and
inflorescence structure a=re
surveyed, and a detailed description o=f
the pollination process
is given, based on observations made
on specimens cultivated i=n
Europe, where vicariant
fungus gnats are the
pollinators. Attraction is
deceptive by mimicking
olfactory, visual and tactile
cues characteristic of fu=ngi
where the gnat sexes
normally meet and females
oviposit. Odours produced
by osmophores (the
spadix appendage or spathe tip) play
the most important<su=b>
part. The identified volatile
compounds are mainly
short-chained aliphatic aldehydes
and alcohols. Flagellifor=m
osmophores of some species, up
to several dm long,
reach the substrate and serve
as conducting
paths. Gnats become imprisoned when
they inadvertently slide =down
the inner wall of the
spathe tube. Its surface
including the spadix is covered
with ablative wax
particles that inactivate the
insects=BB tarsal<s=ub>
pulvilli. This gliding device, in some
species reinforced by zon=es
of imbricate papillae,
is irreversible, and no
movements of floral parts allowing
escape via the spathe=
mouth occur. Anthesis lasts several
weeks. In the male spathe=s,
victims are forced to
wade through the pollen
masses that have accumulated
at the spathe's bottom; t=here
they find an exit hole
formed by local gaping of </font=>the
spathe rims. The female spathes
lack such an aperture. After
potentially depositing
pollen on the stigmas during their efforts<=sub>
to escape, gnats are deta=ined
until death. Except for
an autogamous subspecies of
A. flavum Schott, the
few monoecious taxa of
Arisaema are protogynous and
possibly self-sterile.
In monoecious A. tortuosum
(Wall.)Schott, exit
forming is delayed until pollen releas=e.
Three Arisarum
species that are suspecte=d to
deviate in their floral
syndrome are discussed along with araceous<=sub>
genera possessing similar
one-way pitfall mechanisms.
Copyright 2000 The
Linnean Society of
London Key Words: floral
deception - Mycetophilidae - osmophores - sapromyiophily - Sciaridae.
 
Corresponding author. E-mail: vogel at s1.botanik.univie.ac.at

<font face="Arial Narrow Special G1, Helvetica" size=2>+++<br>
</font><tt>&nbsp;&nbsp;
____&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=sp;=
&nbsp;&nbsp;
____&nbsp;&nbsp;
<font face="Courier New, Courier" size=2 color="#FF0000">E.J.=Gouda</fo=
nt>@bio.uu.nl&nbsp;
<a href="http://www.uu.nl/botgard/"=
eudora="autourl">http://www.uu.nl/botgard/</a><br>
&nbsp; / ___|_ __(_) __&nbsp;&nbsp; / ___| ___&nbsp; _&nbsp;&nbsp;
_&nbsp; __| | __ _&nbsp;&nbsp;&nbsp; Faxnr: +31 30 2535177<br>
&nbsp;| |__ | '__| |/ _| | |&nbsp; _ / _ \| | | |/ _` |/ _` |&nbsp;&nbsp;
Prive:&nbsp;&nbsp; Jungfrau 107<br>
&nbsp;| |___| |&nbsp; | | (_&nbsp; | |_| | (_) | |_| | (_| | (_|
|&nbsp;&nbsp; NL - 3524 WJ&nbsp; Utrecht<br>
&nbsp; \____|_|&nbsp; |_|\__|&nbsp; \____|\___/ \___/
\__,_|\__,_|&nbsp;&nbsp; THE NETHERLANDS&nbsp; (NL)<br>
&nbsp; Curator of
<font face="Courier New, Courier" size=2 color="#FF0000">UNIV=ERSITY
BOTANIC GARDENS</font>,&nbsp; PO Box 80.162, NL-3508 TD UTRECHT <br>
&nbsp; \ Listowner: Alpine-L, Arisaema-L, Bromelia-L, DELTA-L,
Passiflora-L&nbsp;&nbsp;&nbsp; /<br>
&nbsp;&nbsp; \__&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Penstemon-L, Trillium-L (at
Nic.SurfNet.NL)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=p;&=
nbsp;&nbsp;
__/<br>
</html>

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