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Hi Paul & Mary,
On 15-Jul-08, at 12:55 PM, Paul S. Boyer wrote:
> It is possible that you have two different species, because the =20
> various species have different flashing- and flying signals. Some =20
> glow while flying upwards, and some just blink.
It's very likely that these do represent two species. All =20
bioluminescent fireflies have a repertoire of flashing patterns =20
meaning different things, as many as 21 different signal patterns for =20=
some species of Photuris. In all species males fly and emit flashing =20
contact patterns. Females sit on perches (typically on the ground), =20
and if interested, flash back at the males with a different female =20
contact pattern. Males then change their flashing pattern ("I've =20
received your message and am approaching for a landing.").
These patterns are very regular in structure but are temperature =20
dependent (i.e., the cooler it is, the slower the pattern is emitted) =20=
and are further complicated by density. At high densities males of =20
some species will flash in synchrony. Furthermore in some species male =20=
patterns change over the course of the evening. For instance males in =20=
the genus Photuris will start off the evening emitted short-duration =20
single flashes, but within a half-hour change to the short-long (dot-=20
dash) pattern that is their characteristic contact pattern.
If you look carefully at night (once your eye has adjusted to the =20
dark) you can also see colour differences. The light from species in =20
the genus Photinus (P. aquilonis, P. ardens, and P. obscurellus in =20
NS) is generally yellow; that of Photuris (P. fairchildi and P. =20
pennsylvanica in NS) is green; and that of Pyractomena (P. angulata, =20
P. borealis, and P. linearis in NS) is orange-yellow or amber.
> The females, which look partially developed and somewhat grub-like, =20=
> lie in the grass giving off faint glow, to signal the males of their =20=
> presence.
This is only partially true. In some species of lampyrids the females =20=
are so-called larviform, notably in the genera Pleotomus and =20
Pleotomodes, in some species of Photinus, and in Lucidota luteicollis =20=
and Pyractomena nigricans. With the exception of Pyractomena =20
nigricans, which has been recorded in New Brunswick although not in =20
Nova Scotia, none of the others occur in this region. These females =20
resemble larvae in their appearance, have no wings, and cannot fly. =20
Females of other species are brachypterous, i.e. they have reduced =20
wings and cannot fly, although they otherwise look like normal adult =20
beetles. In most species of fireflies, the females are not larviform, =20=
look like adults and are capable of flight.
In the introduced species, Phosphaenus hemipterus (Fourcroy), both =20
males and females are larviform, although there is no evidence at the =20=
moment that this species has persisted in Nova Scotia.
> There is also a species of female who sends false signals to attract =20=
> males of other species, and then grabs and devours them when they =20
> land. And there is even more!
>
> Some years ago, I was trying to photograph lightning bugs, and saw =20
> what appeared to be such a glowing female, and then noticed a male's =20=
> soft light as he descended to meet her. I was eager to record the =20
> courtship, and threw myself on the ground, frantically adjusting =20
> camera and flash in order to catch the moment. I focused so quickly =20=
> that I did not really take time to watch what was going on.
>
> When my film was developed, I was amazed to find, instead of =20
> courtship, simple predation =97 but in this case a large-species male =20=
> was chewing up a male of a smaller species. Somewhere I have the =20
> picture. I have never read of male lightning bugs luring other =20
> males, but this is apparently what I have recorded, on film somewhere.
>
This would certainly be a female Photuris pennsylvanica (DeGeer) =20
preying on the male of another species. If you can find the image, I =20
might be able to identify which one! No male fireflies are predaceous =20=
on other fireflies.
Cheers!
Chris
Christopher Majka
Nova Scotia Museum, 1747 Summer St., Halifax, Nova Scotia, Canada B3H =20=
3A6
c.majka@ns.sympatico.ca
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<html><body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space; ">Hi Paul & =
Mary,<div><br><div><div><div>On 15-Jul-08, at 12:55 PM, Paul S. Boyer =
wrote:</div><br class=3D"Apple-interchange-newline"><blockquote =
type=3D"cite"><div style=3D"word-wrap: break-word; -webkit-nbsp-mode: =
space; -webkit-line-break: after-white-space; "><div>It is possible that =
you have two different species, because the various species have =
different flashing- and flying signals. Some glow while flying =
upwards, and some just =
blink.</div></div></blockquote><div><br></div><div>It's very likely that =
these do represent two species. All bioluminescent fireflies have a =
repertoire of flashing patterns meaning different things, as many as 21 =
different signal patterns for some species of <i>Photuris</i>. In all =
species males fly and emit flashing contact patterns. Females sit =
on perches (typically on the ground), and if interested, flash back at =
the males with a different female contact pattern. Males then change =
their flashing pattern ("I've received your message and am approaching =
for a landing."). </div><div><br></div><div>These patterns are very =
regular in structure but are temperature dependent (i.e., the =
cooler it is, the slower the pattern is emitted) and are further =
complicated by density. At high densities males of some species will =
flash in synchrony. Furthermore in some species male patterns change =
over the course of the evening. For instance males in the genus =
<i>Photuris</i> will start off the =
evening emitted short-duration single flashes, but within a =
half-hour change to the short-long (dot-dash) pattern tha