What is Leaf miner?
[[Image:leaf-miner-damage.jpg|thumb|Leaf miner damage to a [[Horse-chestnut (tree)|horse chestnut]] tree]] [[Image:Leaf mining.jpg|thumb|Leaf with minor miner damage]] [[Image:Leaf-miner-tomato.jpg|thumb|Tomato with leaf miner damage]] A '''leaf miner''' is the [[larva]] of an [[insect]] which lives inside a leaf and eats it. Most leaf-mining insects are [[moth]]s ([[Lepidoptera]]), sawflies ([[sawfly|Symphyta]], a type of [[wasp]]) and flies ([[Diptera]]). Some [[beetle]]s also do this. Like [[woodboring beetle]]s, leaf miners are protected from many [[predator]]s and plant defences by feeding inside a leaf, eating its [[Tissue|tissues]]. It eats only the layers that have the least [[cellulose]]. Also, when attacking ''[[Quercus]] robur'' (English oak), they feed on tissues with lower levels of [[tannin]]. Tannin is a chemical produced in abundance by the [[tree]]. It is not edible.<ref>[https://www.jstor.org/stable/3544471 Paper linking ''Quercus'' species and the leaf miner]</ref> The pattern of the feeding tunnel and the layer of the leaf being mined shows what insect is responsible, sometimes even to the exact [[species]]. The mine often contains [[frass]], or droppings, and the pattern of frass deposition, mine shape, and host plant identity show the species and [[instar]] of the leaf miner. A few mining insects feed in other parts of a plant, such as the surface of a [[fruit]]. It has been suggested that some patterns of leaf variegation may be part of a defensive strategy used by plants. It deceives adult leaf miners into thinking that a leaf has already been preyed upon.<ref>{{cite web |url=http://news.bbc.co.uk/earth/hi/earth_news/newsid_8108000/8108940.stm |title=The plant that pretends to be ill |last1=Walker |first1=Matt |date=19 June 2009 |website=BBC News |access-date=13 April 2016 }}</ref><ref>{{cite journal |last1=Soltau |first1=U. |last2=Dötterl |first2=S. |last3=Liede-Schumann |first3=S. |date=2009 |title=Leaf variegation in ''Caladium steudneriifolium'' (Araceae) – A case of mimicry? |url=