Is there ever a reason why there is a hyphen in Spider-man’s name, but not, in say Iron Man?
When Stan Lee created Spider-Man, he wanted to make sure it wouldn’t be confused with Superman, so he added in the hyphen.
Before creating Superman, Siegel and Shuster wrote "The Reign of the Super-Man.
Batman was originally known as “the Bat-Man,” not to be confused with his adversary, Man-Bat.
The “Wolf-Man” (1941) has been remade as “The Wolfman” (2010). I guess that’s not a superhero, though, is it?
It tends to run that if we use “the” (as in "Look! It’s the Bat-Man!) we use the hyphen, but if we treat the handle as a name (Look! It’s Batman!) we don’t use the hyphen.
Counterexamples abound and there is no consistency in any comic canon.
Yeah, but Marv gets really upset when you write his surname with the hyphen. 
Spider and Bat are nouns
while Iron is also a adjective
Now please post exceptions to this rule.
such as Sandman Plastic Man etc etc
Answer: There is no rhyme or reason; it’s what seemed good at the time.
Actually, very few people ever notice that Spider-Man has a hyphen.
Wait a minute - Betty Brant, Gwen Stacy, Mary Jane Watson, and he still has his hyphen? 
Not true. Although Batman was originally written as Bat-Man, even the earliest comics didn’t always have the hyphen. I know as early as 1940, less than a year from his creation, his name would appear without the hyphen.
Why? The most likely answer is that it depended on who lettering the comic. Additionally, if there was limited space, dropping the hyphen probably helped alot.
The hyphen in Batman, especially in the 1950s and 1960s, was used greatly in the Batman’s arsenal though.
The hyphen in the name Batman had pretty much disappeared by the time Man-Bat appeared in 1970.
I’m no comic book expert, but I’m curious if there’s a corollary between hyphenated superhero names and those created during the “olden days”. Hyphenated words seemed to be a lot more common in the past; to-day, to-night, to-morrow, and so on.
How does any of that equal “not true”?
Oops. When I first read what you wrote, I thought you were saying the hyphen was included in both names so people would not be confused about which character was which.
I stand by the rest of my comment that the hyphen for Batman was probably up to the letterist (I think that’s what their called) on his style and/or to save space.
No problem. I can how my wording could have been misleading. I was trying for pithiness more than precision.
Just to add another confusing data point, the character known in Japan as 鉄腕アトム, Tetsuwan Atomu, lit. “Mighty Atom” has been officially titled both “Astroboy” and (more commonly) “Astro Boy,” but never Astro-Boy, as far as I can tell.
Let’s just split responsibility for it. Your pithiness and my sloppy reading just led to a bad combination.
To tell the truth, the only hyphen that I think most people notice in American comics is the one found in the various X-series, ex. X-Men, X-Factor, etc. Almost everyone I know would either write the names as two separate words or one word without a hyphen.
Now for an interesting trivia I’m sure most people don’t know about superheroes and hyphens… DC and Marvel jointly own the trademark for the term “super-hero” in the USA.
Joe Simon created a character known as Spiderman in the 1950s. It never appeared in any comics, but he took some steps to trademark the character (later known as Silver Spider and, eventually, The Fly; under this name he was a mainstay of the Archie/Red Circle comics). Stan Lee hyphenated the name and trademarked this new version.
Also to differentiate it from Nietzsche’s concept of the Spïdermensch.
As far as I can think of, Spider-Man is the only well-known superhero who still has a hyphen in his name.
One word: Superman, Batman, …
Parsed as two words: Iron Man, Power Man, Wonder Man …
I’m sure there are counter-examples, but I’m interested to note that the above is split on Marvel/DC lines.
Wonder Woman, Power Girl, Elongated Man, Iceman, Sandman.
I don’t think it splits along company lines very well.